As filed with the Securities and Exchange Commission on May 13, 2005

Registration No. 333-                     

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

McKESSON CORPORATION

(Exact name of registrant as specified in its charter)

Copy to:

Gregg A. Noel, Esq.

Skadden, Arps, Slate, Meagher & Flom LLP

300 South Grand Avenue

Los Angeles, California 90071

(213) 687-5000

        Approximate date of commencement of proposed sale to the public: From time to time after this Registration Statement becomes effective.

        If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.    o

        If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.    þ

        If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

        If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

        If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box.    þ

CALCULATION OF REGISTRATION FEE

(footnotes on next page)

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act, or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

(footnotes from previous page)

SUBJECT TO COMPLETION, DATED MAY 13, 2005

PROSPECTUS

$1,500,000,000

McKesson Corporation

Common Stock

Preferred Stock

Depositary Shares

Debt Securities

Warrants

Stock Purchase Contracts

Stock Purchase Units

McKESSON CORPORATION

         The common stock of McKesson Corporation is listed on the New York Stock Exchange under the symbol “MCK.” Our principal executive offices are located at McKesson Plaza, One Post Street, San Francisco, California 94104, and our telephone number is (415) 983-8300.

         We urge you to read carefully this prospectus and the accompanying prospectus supplement, which will describe the specific terms of the securities being offered to you, before you make your investment decision.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus or the accompanying prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus may not be used to sell securities unless accompanied by a prospectus supplement.

The date of this prospectus is                   .

TABLE OF CONTENTS

         Unless otherwise indicated or the context otherwise requires, all references in this prospectus to “McKesson,” “the company,” “we,” “our,” “us” or similar terms refer to McKesson Corporation, together with its subsidiaries.

ABOUT THIS PROSPECTUS

         This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission (the “Commission” or “SEC”), using a “shelf” registration process. Under this shelf process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total dollar amount of $1,500,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under the heading “Where You Can Find More Information.”

WHERE YOU CAN FIND MORE INFORMATION

         We file reports, proxy statements, and other information with the SEC. Such reports, proxy statements, and other information concerning us can be read and copied at the SEC’s Public Reference Room at 450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549 or on the Internet at http://www.sec.gov. Please call the SEC at 1-800-SEC-0330 for further information on the Public Reference Room. Our common stock is listed on the New York Stock Exchange, and these reports, proxy statements and other information are also available for inspection at the offices of the New York Stock Exchange, 20 Broad Street, New York, New York 10005.

         This prospectus is part of a registration statement filed with the SEC by us. The full registration statement can be obtained from the SEC as indicated above, or from us.

         The SEC allows us to “incorporate by reference” the information we file with the SEC. This permits us to disclose important information to you by referring to these filed documents. Any information referred to in this way is considered part of this prospectus, and any information filed with the SEC by us after the date of this prospectus will automatically be deemed to update and supersede this information. We incorporate by reference the following documents that have been filed with the SEC (other than information in such documents that is not deemed to be filed):

         We also incorporate by reference any future filings (other than information in such documents that is not deemed to be filed) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) until we file a post-effective amendment which indicates the termination of the offering of the securities made by this prospectus.

         We will provide without charge upon written or oral request a copy of any or all of the documents that are incorporated by reference into this prospectus, other than exhibits which are specifically incorporated by reference into such documents. Requests should be directed to our Corporate Secretary at McKesson Corporation, McKesson Plaza, One Post Street, San Francisco, California 94104. Our telephone number is (415) 983-8300.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

         This prospectus and the documents incorporated by reference herein include forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Exchange Act. Some of the forward-looking statements can be identified by the use of forward-looking words including, but not limited to, “believes,” “expects,” “anticipates,” “may,” “will,” “should,” “seeks,” “approximately,” “intends,” “plans,” or “estimates” or the negative of those words or other comparable terminology. Forward-looking statements involve risks and uncertainties that could cause actual results to differ materially from those in the forward-looking statements. These factors include, but are not limited to, those discussed under “Additional Factors That May Affect Future Results” in our Annual Report on Form 10-K, in any prospectus supplement related hereto, and in other information contained in our publicly available SEC filings and press releases.

         You should not place undue reliance on any such forward-looking statements, which speak only as of the date hereof. Except to the extent required by federal securities laws, we do not intend to update forward-looking information or to release the results of any future revisions we may make to forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.

McKESSON CORPORATION

         We are a Fortune 15 corporation providing supply, information and care management products and services designed to reduce costs and improve quality across the healthcare industry. We conduct our business through three segments: Pharmaceutical Solutions, Medical-Surgical Solutions and Provider Technologies.

         Our principal executive offices are located at McKesson Plaza, One Post Street, San Francisco, California 94104, and our telephone number is (415) 983-8300.

USE OF PROCEEDS

         Unless otherwise set forth in a prospectus supplement with respect to the proceeds from the sale of the particular securities to which such prospectus supplement relates, we intend to use the net proceeds from the sale of the offered securities for general corporate purposes, including repayment or redemption of outstanding debt or preferred stock, the possible acquisition of related businesses or assets thereof, and working capital needs.

DESCRIPTION OF SECURITIES

         This prospectus contains a summary of our common stock, preferred stock, depositary shares, debt securities, warrants, stock purchase contracts and stock purchase units. These summaries are not meant to be a complete description of each security. The particular terms of any security to be issued pursuant hereto will be set forth in a related prospectus supplement. This prospectus and the accompanying prospectus supplement will contain the material terms and conditions for each security.

DESCRIPTION OF CAPITAL STOCK

         The following descriptions of our capital stock and of certain provisions of Delaware law do not purport to be complete and are subject to and qualified in their entirety by reference to our restated certificate of incorporation and bylaws and the Delaware General Corporation Law (“DGCL”), and, with respect to certain rights of holders of shares of common stock, our rights agreement. Copies of such documents have been filed with the SEC and are filed as exhibits to the registration statement to which this prospectus is a part.

         As of the date hereof, our authorized capital stock consists of 900,000,000 shares, of which 800,000,000 shares are common stock, par value $0.01 per share, and 100,000,000 shares are preferred stock, par value $0.01 per share. As of April 30, 2005, there were 299,979,779 shares of common stock issued and outstanding, and no shares of preferred stock issued and outstanding. Of the preferred stock, 10,000,000 shares have been designated Series A Junior Participating Preferred Stock and reserved for issuance pursuant to our rights agreement. All of our outstanding shares of common stock are fully paid and non-assessable.

         Our common stock is listed on the New York Stock Exchange and the Pacific Exchange under the symbol “MCK.”

         In February 1997, McKesson Financing Trust issued an aggregate of 4,123,720 5% Trust Convertible Preferred Securities. Each trust security is convertible into common stock at any time prior to the close of business on the business day prior to June 1, 2027 (or prior to the date of redemption of the trust security), at the option of the holder, at the rate of 1.3418 shares of common stock for each trust security (equivalent to a conversion price of $37.26 per share of common stock), subject to adjustment in certain circumstances. As described in our Annual Report on Form 10-K for the fiscal year ended March 31, 2005, we do not consolidate our investment in McKesson Financing Trust.

Common Stock

         Dividends Rights. Subject to the dividend rights of the holders of any outstanding series of preferred stock, the holders of shares of common stock are entitled to receive ratably dividends out of assets legally available therefor at such times and in such amounts as our board of directors may from time to time determine.

         Rights Upon Liquidation. Upon liquidation, dissolution or winding up of our affairs, the holders of common stock are entitled to share ratably in our assets that are legally available for distribution, after payment of all debts, other liabilities and any liquidation preferences of outstanding preferred stock.

         Conversion, Redemption and Preemptive Rights. Holders of our common stock have no conversion, redemption, preemptive or similar rights.

         Voting Rights. Each outstanding share of common stock is entitled to one vote on all matters submitted to a vote of stockholders. Our restated certificate of incorporation does not provide for cumulative voting in the election of directors.

Preferred Stock

         Our restated certificate of incorporation authorizes our board of directors, without further stockholder action, to provide for the issuance of up to 100,000,000 shares of preferred stock, in one or more series, and to fix the designations, terms, and relative rights and preferences, including the dividend rate, voting rights, conversion rights, redemption and sinking fund provisions and liquidation values of each of these series. We may amend from time to time our restated certificate of incorporation to increase the number of authorized shares of preferred stock. Any such amendment would require the approval of the holders of a majority of our stock entitled to vote.

         The particular terms of any series of preferred stock that we offer under this prospectus will be described in the applicable prospectus supplement relating to that series of preferred stock. Those terms may include:

         If the terms of any series of preferred stock being offered differ from the terms set forth in this prospectus, those terms will also be disclosed in the applicable prospectus supplement relating to that series of preferred stock. The summary in this prospectus is not complete. You should refer to the certificate of designations establishing a particular series of preferred stock which will be filed with the Secretary of State of the State of Delaware and the SEC in connection with the offering of the preferred stock.

         Each prospectus supplement may describe certain U.S. federal income tax considerations applicable to the purchase, holding and disposition of the preferred stock that prospectus supplement covers.

         Dividend Rights. The preferred stock will be preferred over the common stock as to payment of dividends. Before any dividends or distributions (other than dividends or distributions payable in common stock or other stock ranking junior to that series of preferred stock as to dividends and upon liquidation) on the common stock or other stock ranking junior to that series of preferred stock as to dividends and upon liquidation shall be declared and set apart for payment or paid, the holders of shares of each series of preferred stock (unless otherwise set forth in the applicable prospectus supplement) will be entitled to receive dividends when, as and if declared by our board of directors or, if dividends are cumulative, full cumulative dividends for the current and all prior dividend periods. We will pay those dividends either in cash, shares of preferred stock, or otherwise, at the rate and on the date or dates set forth in the applicable prospectus supplement. With respect to each series of preferred stock that has cumulative dividends, the dividends on each share of the series will be cumulative from the date of issue of the share unless some other date is set forth in the prospectus supplement relating to the series. Accruals of dividends will not bear interest. The applicable prospectus supplement will indicate the relative ranking of the particular series of the preferred stock as to the payment of dividends, as compared with then-existing and future series of preferred stock.

         Rights Upon Liquidation. The preferred stock of each series will be preferred over the common stock and other stock ranking junior to that series of preferred stock as to assets, so that the holders of that series of

preferred stock (unless otherwise set forth in the applicable prospectus supplement) will be entitled to be paid, upon our voluntary or involuntary liquidation, dissolution or winding up, and before any distribution is made to the holders of common stock and other stock ranking junior to that series of preferred stock, the amount set forth in the applicable prospectus supplement. However, in this case the holders of preferred stock of that series will not be entitled to any other or further payment. If upon any liquidation, dissolution or winding up, our net assets are insufficient to permit the payment in full of the respective amounts to which the holders of all outstanding preferred stock are entitled, our entire remaining net assets will be distributed among the holders of each series of preferred stock in amounts proportional to the full amounts to which the holders of each series are entitled, subject to any provisions of any series of preferred stock that rank it junior or senior to other series of preferred stock upon liquidation. The applicable prospectus supplement will indicate the relative ranking of the particular series of the preferred stock upon liquidation, as compared with then-existing and future series of preferred stock.

         Conversion, Redemption or Exchange Rights. The shares of a series of preferred stock will be convertible at the option of the holder of the preferred stock, redeemable at our option or the holder, as applicable, or exchangeable at our option, into another security, in each case, to the extent set forth in the applicable prospectus supplement.

         Voting Rights. Except as indicated in the applicable prospectus supplement or as otherwise from time to time required by law, the holders of preferred stock will have no voting rights.

Anti-Takeover Effects of Provisions of the Our Restated Certificate of Incorporation and Bylaws

         Our restated certificate of incorporation and bylaws contain certain provisions that may be deemed to have an anti-takeover effect and may delay, deter or prevent a tender offer or takeover attempt that a stockholder might consider in its best interest, including those attempts that might result in a premium over the market price for the shares held by stockholders.

         Pursuant to our restated certificate of incorporation, our board of directors is divided into three classes serving staggered three-year terms. Directors can be removed from office only for cause and only by the affirmative vote of the holders of at least a majority of the voting power of the then outstanding shares of any class or series of our capital stock entitled to vote generally in the election of directors. Vacancies and newly created directorships on our board of directors may be filled only by a majority of the remaining directors or by the plurality vote of the stockholders.

         Our restated certificate of incorporation also provides that any action required or permitted to be taken by the holders of common stock may be effected only at an annual or special meeting of such holders, and that stockholders may act in lieu of such meetings only by unanimous written consent. Our bylaws provide that special meetings of holders of common stock may be called only by our Chairman or President or board of directors. Holders of common stock are not permitted to call a special meeting or to require that our board of directors call a special meeting of stockholders.

         Our bylaws establish an advance notice procedure for the nomination, other than by or at the direction of our board of directors, of candidates for election as directors as well as for other stockholder proposals to be considered at annual meetings of stockholders. In general, notice of intent to nominate a director or raise business at such meetings must be received by us not less than 90 nor more than 120 days prior to the date of the annual meeting and must contain certain specified information concerning the person to be nominated or the matters to be brought before the meeting and concerning the stockholder submitting the proposal.

         Our restated certificate of incorporation provides that certain provisions of the bylaws may only be amended by the affirmative vote of the holders of 75% of our outstanding shares entitled to vote. Our restated certificate of incorporation also provides that, in addition to any affirmative vote required by law, the affirmative vote of holders of 80% of our outstanding voting stock and two-thirds of the voting stock other than voting stock held by an interested stockholder shall be necessary to approve certain business combinations proposed by an interested stockholder.

         The foregoing summary is qualified in its entirety by the provisions of our restated certificate of incorporation and bylaws, copies of which have been filed with the SEC.

Rights Plan

         Pursuant to a rights agreement, our board of directors declared a dividend distribution of one right for each outstanding share of common stock to stockholders of record at October 22, 2004. Each right entitles the registered holder to purchase from us a unit consisting of one one-hundredth of a share of Series A Junior Participating Preferred Stock at a purchase price of $100 per unit. The rights expire on October 22, 2014, unless redeemed earlier by our board of directors. The terms of the rights are set forth in a rights agreement between us and a rights agent, a copy of which is filed with the SEC. The following summary outlines certain provisions of the rights agreement and is qualified in its entirety by reference to our rights agreement.

         The rights are attached to all common stock certificates representing shares outstanding at the record date and shares issued between the record date and the distribution date, and no separate rights certificates have been distributed. The rights will separate from the common stock, separate rights certificates will be issued (which will then be the sole evidence of the rights) and a distribution date will occur upon the earlier to occur of:

         (1)            ten business days following the date of a public announcement by us or an acquiring person that there is such an acquiring person (such date is referred to as the “stock acquisition date”),

         (2)            ten business days (or such later date as our board of directors may determine) following commencement of a tender or exchange offer that would result in the offeror beneficially owning 15% or more of the common stock, or

         (3)            ten business days after our of directors determine that the ownership of 10% or more of our outstanding common stock by a person is (A) intended to cause us to repurchase the common stock beneficially owned by such person or to cause pressure on us to take action or enter into a transaction or series of transactions intended to provide such person with short-term financial gain under circumstances where our directors determine that the best long-term interest of the company and its stockholders would not be served by taking such action or entering into such transactions or series of transactions at that time, or (B) is causing, or is reasonably likely to cause, a material adverse impact on us.

         The term “acquiring person” means any person who, together with affiliates and associates, acquires beneficial ownership of shares of our common stock representing 15% or more of our outstanding common stock, but shall not include us, any of our subsidiaries, any of our employee benefit plans, any person or entity organized, appointed or established by us for or pursuant to the terms of such plan, any person who has acquired beneficial ownership of 15% or more of the outstanding shares of common stock as a result of repurchases of stock by us, certain inadvertent actions by institutional or certain other stockholders as of October 22, 2004, or any person who has entered into any agreement or arrangement with us or any subsidiary of ours for an acquisition transaction.

         In the event that a person becomes an acquiring person (except pursuant to an offer for all outstanding shares of common stock which the independent directors determine to be fair to and otherwise in our best interests and in the best interests of our stockholders), each holder of a right will thereafter have the right to receive, upon exercise, common stock (or, in certain circumstances, cash, property or other securities of the company) having a calculated value equal to two times the exercise price of the right. Notwithstanding the foregoing, following the occurrence of such event, all rights that are, or (under certain circumstances specified in the rights agreement) were, beneficially owned by an acquiring person and certain related persons and transferees will be null and void. However, rights are not exercisable following the occurrence of such event until such time as the rights are no longer redeemable as set forth below.

         At any time prior to the tenth day following the stock acquisition date, we may redeem the rights, in whole, but not in part, at a price of $0.0l per right.

         Until a right is exercised, the holder thereof, as such, will have no rights as a stockholder, including without limitation, the right to vote or to receive dividends.

         In general, the rights agreement may be amended by our board of directors (1) prior to the distribution date in any manner, and (2) on or after the distribution date in certain respects including (a) to shorten or

lengthen at any time period and (b) in a manner not adverse to the interests of rights holders. However, amendments extending the redemption period must be made while the rights are still redeemable.

         The rights have certain anti-takeover effects and will cause substantial dilution to a person or group that attempts to acquire us on terms not approved by our board of directors. The rights should not interfere with any merger or other business combination approved by our board of directors, since our board of directors may redeem the rights as provided above.

Section 203 of Delaware General Corporation Law

         We are subject to the “business combination” statute of the DGCL. In general, such statute prohibits a publicly held Delaware corporation from engaging in a “business combination” with any “interested stockholder” for a period of three years after the date of the transaction in which the person became an “interested stockholder,” unless:

         (1)            such transaction is approved by our board of directors prior to the date the interested stockholder obtains such status,

         (2)            upon consummation of such transaction, the “interested stockholder” beneficially owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding those shares owned by (a) persons who are directors and also officers and (b) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer, or

         (3)            the “business combination” is approved by our board of directors and authorized at an annual or special meeting of stockholders by the affirmative vote of at least 66²/3% of the outstanding voting stock which is not owned by the “interested stockholder.”

         A “business combination” includes mergers, asset sales and other transactions resulting in financial benefit to the “interested stockholder.” An “interested stockholder” is a person who, together with affiliates and associates, owns (or within three years, did own) beneficially 15% or more of a corporation’s voting stock. The statute could prohibit or delay mergers or other takeover or change in control attempts with respect to us and, accordingly, may discourage attempts to acquire us.

Certain Effects of Authorized But Unissued Stock

         Our authorized but unissued shares of common stock and preferred stock may be issued without additional stockholder approval and may be utilized for a variety of corporate purposes, including future offerings to raise additional capital or to facilitate corporate acquisitions.

         The issuance of preferred stock could have the effect of delaying or preventing a change in control of us. The issuance of preferred stock could decrease the amount of earnings and assets available for distribution to holders of our common stock or could adversely affect the rights and powers, including voting rights, of such holders. In certain circumstances, such issuance could have the effect of decreasing the market price of our common stock.

         One of the effects of the existence of unissued and unreserved common stock or preferred stock may be to enable our board of directors to issue shares to persons friendly to current management, which could render more difficult or discourage an attempt to obtain control of us by means of a merger, tender offer, proxy contest or otherwise, and thereby protect the continuity of management. Such, additional shares also could be used to dilute the stock ownership of persons seeking to obtain control of us.

         We plan to issue additional shares of common stock (1) in connection with our employee benefit plans and (2) upon conversion of our trust securities. We do not currently have any plans to issue shares of preferred stock, although 10,000,000 shares of Series A Preferred Stock have been designated pursuant to our rights agreement.

Limitation of Liability of Directors

         Our restated certificate of incorporation contains a provision that limits the liability of our directors for monetary damages for breach of fiduciary duty as a director to the fullest extent permitted by the Delaware General Corporation Law. Such limitation does not, however, affect the liability of a director (1) for any breach of the director’s duty of loyalty to us or our stockholders, (2) for acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law, (3) in respect of certain unlawful dividend payments or stock redemptions or purchases and (4) for any transaction from which the director derives an improper personal benefit. The effect of this provision is to eliminate our rights and the rights of our stockholders (through stockholders’ derivative suits) to recover monetary damages against a director for breach of the fiduciary duty of care as a director (including breaches resulting from negligent or grossly negligent behavior) except in the situations described in clauses (1) through (4) above. This provision does not limit or eliminate our rights or the rights of our stockholders to seek non-monetary relief such as an injunction or rescission in the event of a breach of a director’s duty of care. In addition, our directors and officers have indemnification protection.

Transfer Agent and Registrar

         The Bank of New York acts as transfer agent and registrar of our common stock.

Listing

         Our common stock is listed on the New York Stock Exchange under the symbol “MCK”.

DESCRIPTION OF DEPOSITARY SHARES

The following description of the depositary shares does not purport to be complete and is subject to and qualified in its entirety by the Deposit Agreement and the depositary receipt relating to the preferred stock that is attached to the Deposit Agreement. You should read these documents as they, and not this description, define your rights as a holder of depositary shares. Forms of these documents have been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part.

General

         If we elect to offer fractional interests in shares of preferred stock, we will provide for the issuance by a depositary to the public of receipts for depositary shares. Each depositary share will represent fractional interests of preferred stock. We will deposit the shares of preferred stock underlying the depositary shares under a Deposit Agreement between us and a bank or trust company selected by us. The bank or trust company must have its principal office in the United States and a combined capital and surplus of at least $50 million. The depositary receipts will evidence the depositary shares issued under the Deposit Agreement.

         The Deposit Agreement will contain terms applicable to the holders of depositary shares in addition to the terms stated in the depositary receipts. Each owner of depositary shares will be entitled to all the rights and preferences of the preferred stock underlying the depositary shares in proportion to the applicable fractional interest in the underlying shares of preferred stock. The depositary will issue the depositary receipts to individuals purchasing the fractional interests in shares of the related preferred stock according to the terms of the offering described in a prospectus supplement.

Dividends and Other Distributions

         The depositary will distribute all cash dividends or other cash distributions received for the preferred stock to the entitled record holders of depositary shares in proportion to the number of depositary shares that the holder owns on the relevant record date. The depositary will distribute only an amount that can be distributed without attributing to any holder of depositary shares a fraction of one cent. The depositary will add the undistributed balance to and treat it as part of the next sum received by the depositary for distribution to holders of depositary shares.

         If there is a non-cash distribution, the depositary will distribute property received by it to the entitled record holders of depositary shares, in proportion, insofar as possible, to the number of depositary shares owned by the holders, unless the depositary determines, after consultation with us, that it is not feasible to make such distribution. If this occurs, the depositary may, with our approval, sell such property and distribute

the net proceeds from the sale to the holders. The Deposit Agreement also will contain provisions relating to how any subscription or similar rights that we may offer to holders of the preferred stock will be available to the holders of the depositary shares.

Conversion, Exchange and Redemption

         If any series of preferred stock underlying the depositary shares may be converted or exchanged, each record holder of depositary receipts will have the right or obligation to convert or exchange the depositary shares represented by the depositary receipts.

         Whenever we redeem shares of preferred stock held by the depositary, the depositary will redeem, at the same time, the number of depositary shares representing the preferred stock. The depositary will redeem the depositary shares from the proceeds it receives from the corresponding redemption, in whole or in part, of the applicable series of preferred stock. The depositary will mail notice of redemption to the record holders of the depositary shares that are to be redeemed between 30 and 60 days before the date fixed for redemption. The redemption price per depositary share will be equal to the applicable fraction of the redemption price per share on the applicable series of preferred stock. If less than all the depositary shares are to be redeemed, the depositary will select which shares to be redeemed by lot, proportionate allocation or any other method.

         After the date fixed for redemption, the depositary shares called for redemption will no longer be outstanding. When the depositary shares are no longer outstanding, all rights of the holders will end, except the right to receive money, securities or other property payable upon redemption.

Voting

         When the depositary receives notice of a meeting at which the holders of the preferred stock are entitled to vote, the depositary will mail the particulars of the meeting to the record holders of the depositary shares. Each record holder of depositary shares on the record date may instruct the depositary on how to vote the shares of preferred stock underlying the holder’s depositary shares. The depositary will try, if practical, to vote the number of shares of preferred stock underlying the depositary shares according to the instructions. The depositary will abstain from voting shares of the preferred stock to the extent it does not receive specific instructions from the holders of depositary shares representing such preferred stock. We will agree to take all reasonable action requested by the depositary to enable it to vote as instructed.

Record Date

         Whenever (1) any cash dividend or other cash distribution shall become payable, any distribution other than cash shall be made, or any rights, preferences or privileges shall be offered with respect to the preferred stock, or (2) the depositary shall receive notice of any meeting at which holders of preferred stock are entitled to vote or of which holders of preferred stock are entitled to notice, or of the mandatory conversion of or any election on our part to call for the redemption of any preferred stock, the depositary shall in each such instance fix a record date (which shall be the same as the record date for the preferred stock) for the determination of the holders of depositary receipts (x) who shall be entitled to receive such dividend, distribution, rights, preferences or privileges or the net proceeds of the sale thereof or (y) who shall be entitled to give instructions for the exercise of voting rights at any such meeting or to receive notice of such meeting or of such redemption or conversion, subject to the provisions of the Deposit Agreement.

Amendments

         We and the depositary may agree to amend the Deposit Agreement and the depositary receipt evidencing the depositary shares. Any amendment that (a) imposes or increases certain fees, taxes or other charges payable by the holders of the depositary shares as described in the Deposit Agreement or that (b) otherwise prejudices any substantial existing right of holders of depositary shares, will not take effect until 30 days after the depositary has mailed notice of the amendment to the record holders of depositary shares. Any holder of depositary shares that continues to hold its shares at the end of the 30-day period will be deemed to have agreed to the amendment.

Termination

         We may direct the depositary to terminate the Deposit Agreement by mailing a notice of termination to holders of depositary shares at least 30 days prior to termination. In addition, a Deposit Agreement will automatically terminate if:

         The depositary may likewise terminate the Deposit Agreement if at any time 60 days shall have expired after the depositary shall have delivered to us a written notice of its election to resign and a successor depositary shall not have been appointed and accepted its appointment. If any depositary receipts remain outstanding after the date of termination, the depositary thereafter will discontinue the transfer of depositary receipts, will suspend the distribution of dividends to the holders thereof, and will not give any further notices (other than notice of such termination) or perform any further acts under the Deposit Agreement except as provided below and except that the depositary will continue (1) to collect dividends on the preferred stock and any other distributions with respect thereto and (2) to deliver the preferred stock together with such dividends and distributions and the net proceeds of any sales of rights, preferences, privileges or other property, without liability for interest thereon, in exchange for depositary receipts surrendered. At any time after the expiration of two years from the date of termination, the depositary may sell the preferred stock then held by it at public or private sales, at such place or places and upon such terms as it deems proper and may thereafter hold the net proceeds of any such sale, together with any money and other property then held by it, without liability for interest thereon, for the pro rata benefit of the holders of depositary receipts which have not been surrendered.

Payment of Fees and Expenses

         We will pay all fees, charges and expenses of the depositary, including the initial deposit of the preferred stock and any redemption of the preferred stock. Holders of depositary shares will pay transfer and other taxes and governmental charges and any other charges as are stated in the Deposit Agreement for their accounts.

Resignation and Removal of Depositary

         At any time, the depositary may resign by delivering notice to us, and we may remove the depositary. Resignations or removals will take effect upon the appointment of a successor depositary and its acceptance of the appointment. The successor depositary must be appointed within 60 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50 million.

Reports

         The depositary will forward to the holders of depositary shares all reports and communications from us that are delivered to the depositary and that we are required by law, the rules of an applicable securities exchange or our restated certificate of incorporation to furnish to the holders of the preferred stock. Neither we nor the depositary will be liable if the depositary is prevented or delayed by law or any circumstances beyond its control in performing its obligations under the Deposit Agreement. The Deposit Agreement limits our obligations and the depositary’s obligations to performance in good faith of the duties stated in the Deposit Agreement. Neither we nor the depositary will be obligated to prosecute or defend any legal proceeding connected with any depositary shares or preferred stock unless the holders of depositary shares requesting us to do so furnish us with satisfactory indemnity. In performing our obligations, we and the depositary may rely upon the written advice of our counsel or accountants, on any information that competent people provide to us and on documents that we believe are genuine.

DESCRIPTION OF DEBT SECURITIES

         The following descriptions of the debt securities do not purport to be complete and are subject to and qualified in their entirety by reference to the indenture, a form of which has been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part. Any future supplemental indenture or

similar document also will be so filed. You should read the indenture and any supplemental indenture or similar document because they, and not this description, define your rights as holder of our debt securities. All capitalized terms have the meanings specified in the indenture.

         We may issue, from time to time, debt securities, in one or more series, that will consist of either our senior debt (“Senior Debt Securities”), our senior subordinated debt (“Senior Subordinated Debt Securities”), our subordinated debt (“Subordinated Debt Securities”) or our junior subordinated debt (“Junior Subordinated Debt Securities” and, together with the Senior Subordinated Debt Securities and the Subordinated Debt Securities, the “Subordinated Securities”). The debt securities we offer will be issued under an indenture between us and The Bank of New York Trust Company, N.A., acting as trustee. Debt securities, whether senior, senior subordinated, subordinated or junior subordinated, may be issued as convertible debt securities or exchangeable debt securities.

General Terms of the Indenture

         The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit designated by us. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to afford holders of any debt securities protection with respect to our operations, financial condition or transactions involving us.

         We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may, for U.S. federal income tax purposes, be treated as if they were issued with “original issue discount,” or “OID,” because of interest payment and other characteristics. Special U.S. federal income tax considerations applicable to debt securities issued with original issue discount will be described in more detail in any applicable prospectus supplement.

         The applicable prospectus supplement for a series of debt securities that we issue will describe, among other things, the following terms of the offered debt securities:

         The applicable prospectus supplement will set forth certain U.S. federal income tax considerations for holders of any debt securities and the securities exchange or quotation system on which any debt securities are listed or quoted, if any.

         Debt securities issued by us will be structurally subordinated to all indebtedness and other liabilities of our subsidiaries, except to the extent any such subsidiary guarantees or is otherwise obligated to make payment on such debt securities.

         Unless otherwise provided in the applicable prospectus supplement, all securities of any one series need not be issued at the same time and may be issued from time to time without consent of any holder.

Senior Debt Securities

         Payment of the principal of, premium, if any, and interest on Senior Debt Securities will rank on a parity with all of our other unsecured and unsubordinated debt.

Senior Subordinated Debt Securities

         Payment of the principal of, premium, if any, and interest on Senior Subordinated Debt Securities will be junior in right of payment to the prior payment in full of all of our unsubordinated debt. We will set forth in the applicable prospectus supplement relating to any Senior Subordinated Debt Securities the subordination terms of such securities as well as the aggregate amount of outstanding debt, as of the most recent practicable date, that by its terms would be senior to the Senior Subordinated Debt Securities. We will also set forth in such prospectus supplement limitations, if any, on issuance of additional senior debt.

Subordinated Debt Securities

         Payment of the principal of, premium, if any, and interest on Subordinated Debt Securities will be subordinated and junior in right of payment to the prior payment in full of all of our senior and senior subordinated debt. We will set forth in the applicable prospectus supplement relating to any Subordinated Debt Securities the subordination terms of such securities as well as the aggregate amount of outstanding indebtedness, as of the most recent practicable date, that by its terms would be senior to the Subordinated Debt Securities. We will also set forth in such prospectus supplement limitations, if any, on issuance of additional senior debt.

Junior Subordinated Debt Securities

         Payment of the principal of, premium, if any, and interest on Junior Subordinated Debt Securities will be subordinated and junior in right of payment to the prior payment in full of all of our senior, senior subordinated and subordinated debt. We will set forth in the applicable prospectus supplement relating to any Junior Subordinated Debt Securities the subordination terms of such securities as well as the aggregate amount of outstanding debt, as of the most recent practicable date, that by its terms would be senior to the Junior

Subordinated Debt Securities. We will also set forth in such prospectus supplement limitations, if any, on issuance of additional senior debt.

Conversion or Exchange Rights

         Debt securities may be convertible into or exchangeable for other securities or property of McKesson. The terms and conditions of conversion or exchange will be set forth in the applicable prospectus supplement. The terms will include, among others, the following:

Consolidation, Merger or Sale

         We cannot consolidate or merge with or into, or transfer or lease all or substantially all of our assets to, any person unless (a) we will be the continuing corporation or (b) the successor corporation or person to which our assets are transferred or leased is a corporation organized under the laws of the United States, any state of the United States or the District of Columbia and it expressly assumes our obligations on the debt securities and under the indenture. In addition, we cannot effect such a transaction unless immediately after giving effect to such transaction, no default or event of default under the indenture shall have occurred and be continuing. Subject to certain exceptions, when the person to whom our assets are transferred or leased has assumed our obligations under the debt securities and the indenture, we shall be discharged from all our obligations under the debt securities and the indenture, except in limited circumstances.

         This covenant would not apply to any recapitalization transaction, a change of control of McKesson or a highly leveraged transaction, unless the transaction or change of control were structured to include a merger or consolidation or transfer or lease of all or substantially all of our assets.

Events of Default

         Unless otherwise indicated, the term “Event of Default,” when used in the indenture, means any of the following:

         An Event of Default for a particular series of debt securities does not necessarily constitute an Event of Default for any other series of debt securities issued under the indenture. If an Event of Default relating to the payment of interest, principal or any sinking fund installment involving any series of debt securities has occurred and is continuing, the trustee or the holders of not less than 25% in aggregate principal amount of the debt securities of each affected series may declare the entire principal of all the debt securities of that series to be due and payable immediately.

         If an Event of Default relating to the performance of other covenants occurs and is continuing for a period of 90 days after notice of such, or if any other Event of Default occurs and is continuing involving all of the series of Senior Debt Securities, then the trustee or the holders of not less than 25% in aggregate principal amount of all of the series of Senior Debt Securities may declare the entire principal amount of all of the series of Senior Debt Securities due and payable immediately.

         Similarly, if an Event of Default relating to the performance of other covenants occurs and is continuing for a period of 90 days after notice of such, or if any other Event of Default occurs and is continuing involving all of the series of Subordinated Securities, then the trustee or the holders of not less than 25% in aggregate principal amount of all of the series of Subordinated Securities may declare the entire principal amount of all of the series of Subordinated Securities due and payable immediately.

         If, however, the Event of Default relating to the performance of other covenants or any other Event of Default that has occurred and is continuing is for less than all of the series of Senior Debt Securities or Subordinated Securities, as the case may be, then, the trustee or the holders of not less than 25% in aggregate principal amount of each affected series of the Senior Debt Securities or the Subordinated Securities, as the case may be, may declare the entire principal amount of all debt securities of such affected series due and payable immediately. The holders of not less than a majority in aggregate principal amount of the debt securities of a series may, after satisfying conditions, rescind and annul any of the above-described declarations and consequences involving the series.

         If an Event of Default relating to events in bankruptcy, insolvency or reorganization of McKesson occurs and is continuing, then the principal amount of all of the debt securities outstanding, and any accrued interest, will automatically become due and payable immediately, without any declaration or other act by the trustee or any holder.

         The indenture imposes limitations on suits brought by holders of debt securities against us. Except as provided below, no holder of debt securities of any series may institute any action against us under the indenture unless:

         Notwithstanding the foregoing, each holder of debt securities of any series has the right, which is absolute and unconditional, to receive payment of the principal of and premium and interest, if any, on such debt securities when due and to institute suit for the enforcement of any such payment, and such rights may not be impaired without the consent of that holder of debt securities.

         We will be required to file annually with the Trustee a certificate, signed by an officer of McKesson, stating whether or not the officer knows of any default by us in the performance, observance or fulfillment of any condition or covenant of the indenture.

Registered Global Securities

         We may issue the debt securities of a series in whole or in part in the form of one or more fully registered global securities that we will deposit with a depositary or with a nominee for a depositary identified in the applicable prospectus supplement and registered in the name of such depositary or nominee. In such case, we will issue one or more registered global securities denominated in an amount equal to the aggregate principal amount of all of the debt securities of the series to be issued and represented by such registered global security or securities.

         Unless and until it is exchanged in whole or in part for debt securities in definitive registered form, a registered global security may not be transferred except as a whole:

         The prospectus supplement relating to a series of debt securities will describe the specific terms of the depositary arrangement with respect to any portion of such series represented by a registered global security. We anticipate that the following provisions will apply to all depositary arrangements for debt securities:

         The laws of some states may require that certain purchasers of securities take physical delivery of the securities in definitive form. These laws may limit the ability of those persons to own, transfer or pledge beneficial interests in registered global securities.

         So long as the depositary for a registered global security, or its nominee, is the registered owner of the registered global security, the depositary or the nominee, as the case may be, will be considered the sole owner or holder of the debt securities represented by the registered global security for all purposes under the indenture. Except as set forth below, owners of beneficial interests in a registered global security:

         Accordingly, each person owning a beneficial interest in a registered global security must rely on the procedures of the depositary for the registered global security and, if the person is not a participant, on the procedures of a participant through which the person owns its interest, to exercise any rights of a holder under the indenture.

         We understand that under existing industry practices, if we request any action of holders or if an owner of a beneficial interest in a registered global security desires to give or take any action that a holder is entitled to give or take under the indenture, the depositary for the registered global security would authorize the participants holding the relevant beneficial interests to give or take the action, and those participants would authorize beneficial owners owning through those participants to give or take the action or would otherwise act upon the instructions of beneficial owners holding through them.

         We will make payments of principal and premium, if any, and interest, if any, on debt securities represented by a registered global security registered in the name of a depositary or its nominee to the depositary or its nominee, as the case may be, as the registered owners of the registered global security. None

of McKesson, the trustee or any other agent of McKesson or the trustee will be responsible or liable for any aspect of the records relating to, or payments made on account of, beneficial ownership interests in the registered global security or for maintaining, supervising or reviewing any records relating to the beneficial ownership interests.

         We expect that the depositary for any debt securities represented by a registered global security, upon receipt of any payments of principal and premium, if any, and interest, if any, in respect of the registered global security, will immediately credit participants’ accounts with payments in amounts proportionate to their respective beneficial interests in the registered global security as shown on the records of the depositary. We also expect that standing customer instructions and customary practices will govern payments by participants to owners of beneficial interests in the registered global security held through the participants, as is now the case with the securities held for the accounts of customers in bearer form or registered in “street name.” We also expect that any of these payments will be the responsibility of the participants.

         If the depositary for any debt securities represented by a registered global security is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Exchange Act, we will appoint an eligible successor depositary. If we fail to appoint an eligible successor depositary within 90 days, we will issue the debt securities in definitive form in exchange for the registered global security. In addition, we may at any time and in our sole discretion decide not to have any of the debt securities of a series represented by one or more registered global securities. In such event, we will issue debt securities of that series in a definitive form in exchange for all of the registered global securities representing the debt securities. The trustee will register any debt securities issued in definitive form in exchange for a registered global security in such name or names as the depositary, based upon instructions from its participants, shall instruct the trustee.

         We may also issue bearer debt securities of a series in the form of one or more global securities, referred to as “bearer global securities.” We will deposit these bearer global securities with a common depositary for Euroclear System and Clearstream Bank Luxembourg, Societe Anonyme, or with a nominee for the depositary identified in the prospectus supplement relating to that series. The prospectus supplement relating to a series of debt securities represented by a bearer global security will describe the specific terms and procedures, including the specific terms of the depositary arrangement and any specific procedures for the issuance of debt securities in definitive form in exchange for a bearer global security, with respect to the portion of the series represented by a bearer global security.

Discharge, Defeasance and Covenant Defeasance

         We can discharge or defease our obligations under the indenture as set forth below. Unless otherwise set forth in the applicable prospectus supplement, the subordination provisions applicable to any Subordinated Securities will be expressly made subject to the discharge and defeasance provisions of the indenture.

         We may discharge our obligations to holders of any series of debt securities that have not already been delivered to the trustee for cancellation and that have either become due and payable or are by their terms to become due and payable within one year (or are scheduled for redemption within one year). We may effect a discharge by irrevocably depositing with the trustee cash or U.S. government obligations, as trust funds, in an amount certified to be sufficient to pay when due, whether at maturity, upon redemption or otherwise, the principal of, premium, if any, and interest on the debt securities and any mandatory sinking fund payments.

         Unless otherwise provided in the applicable prospectus supplement, we may also discharge any and all of our obligations to holders of any series of debt securities at any time (“legal defeasance”). We also may be released from the obligations imposed by any covenants of any outstanding series of debt securities and provisions of the indenture, and we may omit to comply with those covenants without creating an Event of Default (“covenant defeasance”). We may effect defeasance and covenant defeasance only if, among other things:

         Although we may discharge or defease our obligations under the indenture as described in the two preceding paragraphs, we may not avoid, among other things, our duty to register the transfer or exchange of any series of debt securities, to replace any temporary, mutilated, destroyed, lost or stolen series of debt securities or to maintain an office or agency in respect of any series of debt securities.

Modification of the Indenture

         The indenture provides that we and the trustee may enter into supplemental indentures without the consent of the holders of debt securities to:

         The indenture also provides that we and the trustee may, with the consent of the holders of not less than a majority in aggregate principal amount of debt securities of all series of Senior Debt Securities or Subordinated Securities, as the case may be, then outstanding and affected (voting as one class), add any provisions to, or change in any manner, eliminate or modify in any way the provisions of, the indenture or modify in any manner the rights of the holders of the debt securities. We and the trustee may not, however, without the consent of the holder of each outstanding debt security affected thereby:

Concerning the Trustee

         The indenture provides that there may be more than one trustee under the indenture, each with respect to one or more series of debt securities. If there are different trustees for different series of debt securities, each trustee will be a trustee of a trust under the indenture separate and apart from the trust administered by any other trustee under the indenture. Except as otherwise indicated in this prospectus or any prospectus supplement, any action permitted to be taken by a trustee may be taken by such trustee only with respect to the one or more series of debt securities for which it is the trustee under the indenture. Any trustee under the indenture may resign or be removed with respect to one or more series of debt securities. All payments of principal of, premium, if any, and interest on, and all registration, transfer, exchange, authentication and delivery (including authentication and delivery on original issuance of the debt securities) of, the debt securities of a series will be effected by the trustee with respect to that series at an office designated by the trustee in New York, New York.

         The indenture contains limitations on the right of the trustee, should it become a creditor of McKesson, to obtain payment of claims in some cases or to realize on certain property received in respect of any such claim as security or otherwise. The trustee may engage in other transactions. If it acquires any conflicting interest relating to any duties with respect to the debt securities, however, it must eliminate the conflict or resign as trustee.

         The holders of a majority in aggregate principal amount of any series of debt securities then outstanding will have the right to direct the time, method and place of conducting any proceeding for exercising any remedy available to the trustee with respect to such series of debt securities, provided that the direction would not conflict with any rule of law or with the indenture, would not be unduly prejudicial to the rights of another holder of the debt securities, and would not involve any trustee in personal liability. The indenture provides that in case an Event of Default shall occur and be known to any trustee and not be cured, the trustee must use the same degree of care as a prudent person would use in the conduct of his or her own affairs in the exercise of the trustee’s power. Subject to these provisions, the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request of any of the holders of the debt securities, unless they shall have offered to the trustee security and indemnity satisfactory to the trustee.

No Individual Liability of Incorporators, Stockholders, Officers or Directors

         The indenture provides that no incorporator and no past, present or future stockholder, officer or director, of McKesson or any successor corporation in their capacity as such shall have any individual liability for any of our obligations, covenants or agreements under the debt securities or the indenture.

Governing Law

         The indenture and the debt securities will be governed by, and construed in accordance with, the laws of the State of New York, including, without limitation, Sections 5-1401 and 5-1402 of the New York General Obligations Law and New York Civil Practice Law and Rules 327(b).

DESCRIPTION OF WARRANTS

General

         We may issue debt warrants for the purchase of debt securities or stock warrants for the purchase of preferred stock or common stock.

         The warrants will be issued under warrant agreements to be entered into between us and a bank or trust company, as warrant agent, all to be set forth in the applicable prospectus supplement relating to any or all warrants in respect of which this prospectus is being delivered. Copies of the form of agreement for each warrant, including the forms of certificates representing the warrants reflecting the provisions to be included in such agreements that will be entered into with respect to the particular offerings of each type of warrant are filed as exhibits to the registration statement of which this prospectus is a part.

         The following description sets forth certain general terms and provisions of the warrants to which any prospectus supplement may relate. The particular terms of the warrants to which any prospectus supplement may relate and the extent, if any, to which such general provisions may apply to the warrants so offered will be described in the applicable prospectus supplement. The following summary of certain provisions of the warrants, warrant agreements and warrant certificates does not purport to be complete and is subject to, and is qualified in its entirety by express reference to, all the provisions of the warrant agreements and warrant certificates, including the definitions therein of certain terms.

Debt Warrants

         General. Reference is made to the applicable prospectus supplement for the terms of debt warrants in respect of which this prospectus is being delivered, the debt securities warrant agreement relating to such debt warrants and the debt warrant certificates representing such debt warrants, including the following:

         The debt warrant certificates will be exchangeable for new debt warrant certificates of different denominations and debt warrants may be exercised at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Prior to the exercise of their debt warrants, holders of debt warrants will not have any of the rights of holders of the debt securities purchasable upon such exercise and will not be entitled to any payments of principal and premium, if any, and interest, if any, on the debt securities purchasable upon such exercise.

         Exercise of Debt Warrants. Each debt warrant will entitle the holder to purchase for cash such principal amount of debt securities at such exercise price as shall in each case be set forth in, or be

determinable as set forth in, the applicable prospectus supplement relating to the debt warrants offered thereby. Unless otherwise specified in the applicable prospectus supplement, debt warrants may be exercised at any time up to 5:00 p.m., New York City time, on the expiration date set forth in the applicable prospectus supplement. After 5:00 p.m., New York City time, on the expiration date, unexercised debt warrants will become void.

         Debt warrants may be exercised as set forth in the applicable prospectus supplement relating to the debt warrants. Upon receipt of payment and the debt warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will, as soon as practicable, forward the debt securities purchasable upon such exercise. If less than all of the debt warrants represented by such debt warrant certificate are exercised, a new debt warrant certificate will be issued for the remaining amount of debt warrants.

Stock Warrants

         General. Reference is made to the applicable prospectus supplement for the terms of stock warrants in respect of which this prospectus is being delivered, the stock warrant agreement relating to such stock warrants and the stock warrant certificates representing such stock warrants, including the following:

         The stock warrant certificates will be exchangeable for new stock warrant certificates of different denominations and stock warrants may be exercised at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Prior to the exercise of their stock warrants, holders of stock warrants will not have any of the rights of holders of shares of capital stock purchasable upon such exercise, and will not be entitled to any dividend payments on such capital stock purchasable upon such exercise.

         Exercise of Stock Warrants. Each stock warrant will entitle the holder to purchase for cash such number of shares of preferred stock or common stock, as the case may be, at such exercise price as shall in each case be set forth in, or be determinable as set forth in, the applicable prospectus supplement relating to the stock warrants offered thereby. Unless otherwise specified in the applicable prospectus supplement, stock warrants may be exercised at any time up to 5:00 p.m., New York City time, on the expiration date set forth in the applicable prospectus supplement. After 5:00 p.m., New York City time, on the expiration date, unexercised stock warrants will become void.

         Stock warrants may be exercised as set forth in the applicable prospectus supplement relating thereto. Upon receipt of payment and the stock warrant certificates properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement,

we will, as soon as practicable, forward a certificate representing the number of shares of capital stock purchasable upon such exercise. If less than all of the stock warrants represented by such stock warrant certificate are exercised, a new stock warrant certificate will be issued for the remaining amount of stock warrants.

DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE UNITS

         We may issue stock purchase contracts, representing contracts obligating holders to purchase from us, and requiring us to sell to the holders, a specified number of shares of common stock at a future date or dates. The price per share of common stock may be fixed at the time the stock purchase contracts are issued or may be determined by reference to a specific formula set forth in the stock purchase contracts. The stock purchase contracts may be issued separately or as a part of units, or stock purchase units, consisting of a stock purchase contract and either (x) senior debt securities, senior subordinated debt securities, subordinated debt securities or junior subordinated debt securities, or (y) debt obligations of third parties, including U.S. Treasury securities, in each case, securing the holder’s obligations to purchase the common stock under the stock purchase contracts. The stock purchase contracts may require us to make periodic payments to the holders of the stock purchase contracts or vice versa, and such payments may be unsecured or prefunded on some basis. The stock purchase contracts may require holders to secure their obligations thereunder in a specified manner and in certain circumstances we may deliver newly issued prepaid stock purchase contracts, or prepaid securities, upon release to a holder of any collateral securing such holder’s obligations under the original stock purchase contract.

         The applicable prospectus supplement will describe the terms of any stock purchase contracts or stock purchase units and, if applicable, prepaid securities. The description in the prospectus supplement will not purport to be complete and will be qualified in its entirety by reference to the stock purchase contracts, the collateral arrangements and depositary arrangements, if applicable, relating to such stock purchase contracts or stock purchase units and, if applicable, the prepaid securities and the document pursuant to which such prepaid securities will be issued.

PLAN OF DISTRIBUTION

         McKesson may sell common stock, preferred stock, depositary shares, debt securities, warrants, stock purchase contracts or stock purchase units in one or more of the following ways from time to time:

         The prospectus supplements relating to an offering of offered securities will set forth the terms of such offering, including:

         Any initial public offering prices, discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

         If underwriters are used in the sale, the underwriters will acquire the offered securities for their own account and may resell them from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The offered securities may be offered either to the public through underwriting syndicates represented by one or more managing underwriters or by one or more underwriters without a syndicate. Unless otherwise set forth in a prospectus supplement, the obligations of the underwriters to purchase any series of securities will be subject to certain conditions precedent, and the underwriters will be obligated to purchase all of such series of securities, if any are purchased.

         In connection with underwritten offerings of the offered securities and in accordance with applicable law and industry practice, underwriters may over-allot or effect transactions that stabilize, maintain or otherwise affect the market price of the offered securities at levels above those that might otherwise prevail in the open market, including by entering stabilizing bids, effecting syndicate covering transactions or imposing penalty bids, each of which is described below.

         These transactions may be effected on the NYSE, in the over-the-counter market, or otherwise. Underwriters are not required to engage in any of these activities, or to continue such activities if commenced.

         If a dealer is used in the sale, McKesson will sell such offered securities to the dealer, as principal. The dealer may then resell the offered securities to the public at varying prices to be determined by that dealer at the time for resale. The names of the dealers and the terms of the transaction will be set forth in the prospectus supplement relating to that transaction.

         Offered securities may be sold directly by McKesson to one or more institutional purchasers, or through agents designated by McKesson from time to time, at a fixed price or prices, which may be changed, or at varying prices determined at the time of sale. Any agent involved in the offer or sale of the offered securities in respect of which this prospectus is delivered will be named, and any commissions payable by McKesson to such agent will be set forth, in the prospectus supplement relating to that offering. Unless otherwise indicated in such prospectus supplement, any such agent will be acting on a best efforts basis for the period of its appointment.

         Underwriters, dealers and agents may be entitled under agreements entered into with us to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments that the underwriters, dealers or agents may be required to make in respect thereof. Underwriters, dealers and agents may be customers of, engage in transactions with, or perform services for us and our affiliates in the ordinary course of business.

         Other than our common stock, which is listed on the New York Stock Exchange, each of the securities issued hereunder will be a new issue of securities, will have no prior trading market, and may or may not be listed on a national securities exchange or the Nasdaq Stock Market. Any common stock sold pursuant to a prospectus supplement will be listed on the New York Stock Exchange, subject to official notice of issuance. Any underwriters to whom McKesson sells securities for public offering and sale may make a market in the securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. We cannot assure you that there will be a market for the offered securities.

LEGAL MATTERS

         The validity of the securities being offered hereby is being passed upon for McKesson Corporation by Skadden, Arps, Slate, Meagher & Flom LLP, Los Angeles, California.

EXPERTS

         The consolidated financial statements, financial statement schedule and management’s report on the effectiveness of internal control over financial reporting incorporated in this prospectus by reference from McKesson Corporation’s Annual Report on Form 10-K for the year ended March 31, 2005 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein, and have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

         The following table sets forth the expenses to be borne by McKesson Corporation in connection with the offerings described in this Registration Statement. All expenses, other than the SEC registration fee, are estimates.

         Article VIII of the Amended and Restated By-Laws of McKesson Corporation (the “Bylaws”), in accordance with the provisions of Section 145 of the General Corporation Law of the State of Delaware (the “DGCL”), provides that McKesson shall indemnify any person in connection with any threatened, pending or completed legal proceeding (other than a legal proceeding by or in the right of McKesson) by reason of the fact that he is or was a director or officer of McKesson or is or was serving at the request of McKesson as a director, officer, employee or agent of another corporation, partnership or other enterprise against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such legal proceeding if he acted in good faith and in a manner that he reasonably believed to be in or not opposed to the best interests of McKesson, and, with respect to any criminal action or proceeding, if he had no reasonable cause to believe that his conduct was unlawful. If the legal proceeding is by or in the right of McKesson, the director or officer shall be indemnified by McKesson against expenses (including attorneys’ fees) actually and reasonably incurred in connection with the defense or settlement of such legal proceeding if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of McKesson, except that he may not be indemnified in respect of any claim, issue or matter as to which he shall have been adjudged to be liable to McKesson unless a court determines otherwise.

         Article VIII of McKesson’s Bylaws allows McKesson to maintain director and officer liability insurance on behalf of any person who is or was a director or officer of McKesson or such person who serves or served as director, officer, employee or agent of another corporation, partnership or other enterprise at the request of McKesson.

         Article VI of McKesson’s Restated Certificate of Incorporation, in accordance with Section 102(b)(7) of the DGCL, provides that no director of McKesson shall be personally liable to McKesson or its stockholders for monetary damages for any breach of his fiduciary duty as a director; provided, however, that such clause shall not apply to any liability of a director (1) for any breach of his duty of loyalty to McKesson or its stockholders, (2) for acts or omission that are not in good faith or involve intentional misconduct or a knowing violation of the law, (3) under Section 174 of the DGCL, or (4) for any transaction from which the director derived an improper personal benefit.

         The underwriting agreement to be entered into in connection with an offering of the securities will contain provisions which indemnify the officers and directors of McKesson in certain circumstances.

         It is the opinion of the Securities and Exchange Commission that indemnification of directors and officers for liabilities arising under the Securities Act of 1933 is against public policy and is unenforceable pursuant to Section 14 of the Securities Act of 1933.

*To be filed by amendment or incorporated by reference prior to the offering of securities.

ITEM 17. Undertakings.

         (a)            The undersigned registrant hereby undertakes:

                  (1)            To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) shall not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the Commission by either registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement.

                  (2)            That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

                  (3)            To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

         (b)            The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual reports pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

         (c)            Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit, or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of their counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by them is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, McKesson Corporation certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Francisco, State of California, on the 13th day of May, 2005.

         Pursuant to the requirements of the Securities Act of 1933, this Registration Statement on Form S-3 has been signed below by the following persons in the capacities and on the dates indicated.

EXHIBIT INDEX

*To be filed by amendment or incorporated by reference prior to the offering of securities.