As filed with the Securities and Exchange Commission on March 25, 2010 Registration No. 333-161701 ________________________________________________________________________________ SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 POST EFFECTIVE AMENDMENT NO. 1 TO REGISTRATION STATTEMENT ON FORM S-4 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 PURESPECTRUM, INC. (Exact name of Registrant as specified in its charter) Delaware 41-2233302 (State or other jurisdiction of (I.R.S. Employee incorporation or organization) Identification Number) 340 Eisenhower Dr. Bldg. 600, Suite 610 Savannah, Georgia 31406 (912) 961-4980 (Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant's Principal Executive Offices) ___________________________ Delaware Corporation Organizers, Inc. 1201 North Market Street, 18th Floor Wilmington, Delaware 19801 (302) 658-9200 (Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service) ___________________________ Copies to: Daniel D. Dinur, Esq. and David Michael Conner, Esq. Dinur and DeLuca, LLP Bouhan Williams & Levy, LLP One Lakeside Commons The Armstrong House 990 Hammond Drive, Suite 760 477 Bull Street Atlanta, Georgia 30328 Savannah, Georgia 31402 (770) 395-3170 (912) 236-2491 Approximate date of commencement of proposed sale to the public: Not applicable. If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. [ ] 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. [ ] -1- 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. [ ] 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. [ ] If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Securities and Exchange Commission pursuant to Rule 462(e) under the Securities Act, check the following box. [ ] If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. [ ] Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definition of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. Large Accelerated Filer [ ] Accelerated Filer [ ] Non-Accelerated Filer [ ] Smaller reporting company [X] (Do not check if a smaller reporting company) EXPLANATORY NOTE - DEREGISTRATION OF SECURITIES This Post-Effective Amendment relates to Registration Statement No. 333-161701 to Form S-4 and is being filed to deregister any securities of PureSpectrum, Inc., a Delaware corporation, f/k/a International Medical Staffing, Inc. ("PSRU"), which were not issued in the exchange pursuant to the C-Reorg transaction described in the Registration Statement and which was consummated on November 3, 2009. These securities are as follows: - 1,137,910 shares of common stock, $0.0001 par value, issuable to the shareholders of PureSpectrum, Inc., a Nevada corporation ("PSPM") in exchange for the shares of PSPM common stock held by them on the record date,who did not tender those shares in the exchange; - 1,449,298 warrants to purchase common stock registered in the Registration Statement which have expired as of March 15, 2010, without having been exercised (the "Expired Warrants"); and - 1,449,298 shares of common stock underlying the Expired Warrants. As of March 15, 2010, after the deadline for the completion of the exchanges, (a) all of the remaining 194,967,438 shares of PSRU common stock registered in the Registration Statement were issued to former PSPM shareholders, and (b) all of the remaining 43,956,173 unexpired warrants and shares of common stock underlying such warrants retain their registered status. Pursuant to the undertakings contained in Registration Statement No. 333-161701 to remove from registration, by means of a Post-Effective Amendment, any securities which remain unsold at the termination of the offering, PSRU is filing this Post-Effective Amendment to Registration Statement No. 333-161701 to Form S-4 to deregister the above unsold securities. -2- SIGNATURES Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing this Post-Effective Amendment No. 1 to Form S-4 and has duly caused this Post-Effective Amendment No. 1 to Form S-4 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Savannah, State of Georgia, on March 25, 2010. Pure Spectrum, Inc. (Registrant) By: /S/ Lee L. Vanatta ------------------ Name: Lee L. Vanatta Title: President, Principal Executive Officer and Director Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment No. 1 to Form S-4 has been signed by the following persons in the capacities and on the dates indicated. Signature Title Date --------- ----- ---- /S/ Lee L. Vanatta President and Director March 24, 2010 ------------------ [Principal Executive Officer] Lee L. Vanatta /S/ William R. Norton Executive Vice President, March 24, 2010 --------------------- Secretary and Director William R. Norton /S/ Susan W. Norton Vice President of Administration March 24, 2010 ------------------- and Acting Chief Financial Susan W. Norton Officer [Principal Financial and Accounting Officer] /S/ David Michael Conner Director March 24, 2010 ------------------------ David Michael Conner /S/ Bill G. Garlan Director March 24, 2010 ------------------ Bill G. Garlan /S/ Robert E. James, II Director March 24, 2010 ----------------------- Robert E. James, II -3-