Washington, D.C. 20549

                           Schedule 13G

            Under the Securities Exchange Act of 1934
                        (Amendment No. 5)*

                           RED HAT, INC.
                         (Name of Issuer)

                           Common Stock
                  (Title of Class of Securities)

                          (CUSIP Number)

Check the following box if a fee is being paid with this statement
____.  (A fee is not required only if the filing person: (1) has a
previous statement on file reporting beneficial ownership of more
than five percent of the class of securities described in Item 1;
and (2) has filed no amendment subsequent thereto reporting
beneficial ownership of five percent or less of such class.)  (See
Rule 13d-7.)

*The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to the
subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided
in a prior cover page.

The information required in the remainder of this cover page shall
not be deemed to be "filed" for the purpose of Section 18 of the
Securities Exchange Act of 1934 ("Act") or otherwise subject to the
liabilities of that section of the Act but shall be subject to all
other provisions of the Act (however, see the Notes).

                 (Continued on following page(s))

                        Page 1 of 5 Pages
CUSIP NO. 756577102              13G           Page 2 of 5 Pages

1   Name of Reporting Person
    S.S. or I.R.S. Identification No. of Above Person


2   Check the Appropriate Box if a Member of a Group*
                                                        (a) ____
    NOT APPLICABLE                                     (b) ____

3   SEC Use Only


4   Citizenship or Place of Organization


Number of       5  Sole Voting Power
Shares             5,896,990

Beneficially    6  Shared Voting Power
Owned By Each      NONE

Reporting       7  Sole Dispositive Power
Person             20,196,282

With            8  Shared Dispositive Power


9   Aggregate Amount Beneficially Owned by Each Reporting Person


10  Check Box if the Aggregate Amount in Row (9) Excludes Certain


11  Percent of Class Represented by Amount in Row 9


12  Type of Reporting Person*

         **Any shares reported in Items 5 and 6 are also
                       reported in Item 7.

Item 1(a)  Name of Issuer:

           Reference is made to page 1 of this Schedule 13G

Item 1(b)  Address of Issuer's Principal Executive Offices:

           1801 Varsity Drive, Raleigh, North Carolina 27606-2072

Item 2(a)  Name of Person(s) Filing:

           (1)  T. Rowe Price Associates, Inc. ("Price Associates")

           (2) ___________________________________

_____      Attached as Exhibit A is a copy of an agreement between
           the Persons Filing (as specified hereinabove) that this
           Schedule 13G is being filed on behalf of each of them.

Item 2(b)  Address of Principal Business Office:

           100 E. Pratt Street, Baltimore, Maryland 21202

Item 2(c)  Citizenship or Place of Organization:

           (1) Maryland

           (2) ___________________________________

Item 2(d)  Title of Class of Securities:

           Reference is made to page 1 of this Schedule 13G

Item 2(e)  CUSIP Number: 756577102

Item 3     The person filing this Schedule 13G is an:

  X        Investment Adviser registered under Section 203 of the
           Investment Advisers Act of 1940

_____      Investment Company registered under Section 8 of the
           Investment Company Act of 1940

Item 5  Ownership of Five Percent or Less of a Class.

  X     Not Applicable.

_____   This statement is being filed to report the fact that, as
        of the date of this report, the reporting person(s) has
        (have) ceased to be the beneficial owner of more than five
        percent of the class of securities.

Item 6  Ownership of More than Five Percent on Behalf of Another

        (1) Price Associates does not serve as custodian of the
            assets of any of its clients; accordingly, in each
            instance only the client or the client's custodian or
            trustee bank has the right to receive dividends paid
            with respect to, and proceeds from the sale of, such

            The ultimate power to direct the receipt of dividends
            paid with respect to, and the proceeds from the sale
            of, such securities, is vested in the individual and
            institutional clients which Price Associates serves as
            investment adviser.  Any and all discretionary
            authority which has been delegated to Price Associates
            may be revoked in whole or in part at any time.

            Except as may be indicated if this is a joint filing
            with one of the registered investment companies
            sponsored by Price Associates which it also serves as
            investment adviser ("T. Rowe Price Funds"), not more
            than 5% of the class of such securities is owned by any
            one client subject to the investment advice of Price

        (2) With respect to securities owned by any one of the T.
            Rowe Price Funds, only State Street Bank and Trust
            Company, as custodian for each of such Funds, has the
            right to receive dividends paid with respect to, and
            proceeds from the sale of, such securities.  No other
            person is known to have such right, except that the
            shareholders of each such Fund participate
            proportionately in any dividends and distributions so

Item 7  Identification and Classification of the Subsidiary Which
        Acquired the Security Being Reported on By the Parent
        Holding Company.

        Not Applicable.

Item 8  Identification and Classification of Members of the Group.

        Not Applicable.

Item 9    Notice of Dissolution of Group.

          Not Applicable.

Item 10   Certification.

          By signing below I (we) certify that, to the best of my
          (our) knowledge and belief, the securities referred to
          above were acquired in the ordinary course of business
          and were not acquired for the purpose of and do not have
          the effect of changing or influencing the control of the
          issuer of such securities and were not acquired in
          connection with or as a participant in any transaction
          having such purpose or effect.  T. Rowe Price Associates,
          Inc. hereby declares and affirms that the filing of this
          Schedule 13G shall not be construed as an admission that
          Price Associates is the beneficial owner of the
          securities referred to, which beneficial ownership is
          expressly denied.


          After reasonable inquiry and to the best of my (our)
          knowledge and belief, I (we) certify that the information
          set forth in this statement is true, complete and

              Dated:  October 10, 2006


              By: /s/ Henry H. Hopkins
                  Henry H. Hopkins, Vice President

Note:     This Schedule 13G, including all exhibits, must be filed
          with the Securities and Exchange Commission, and a copy
          hereof must be sent to the issuer by registered or
          certified mail not later than February 14th following the
          calendar year covered by the statement or within the time
          specified in Rule 13d-1(b)(2), if applicable.