AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 2, 2000 REGISTRATION STATEMENT NO. 333-33770 - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 ------------------------ POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 --------------- REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 MILLENNIUM PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) DELAWARE 04-3177038 (State or other jurisdiction (I.R.S. Employer of Identification Number) incorporation or organization) 75 SIDNEY STREET CAMBRIDGE, MASSACHUSETTS 02139 617-679-7000 (Address, including zip code, and telephone number, including area code, of registrant's principal executive offices) JOHN B. DOUGLAS III, ESQ. SENIOR VICE PRESIDENT AND GENERAL COUNSEL MILLENNIUM PHARMACEUTICALS, INC. 75 SIDNEY STREET CAMBRIDGE, MASSACHUSETTS 02139 (617) 679-7000 (Name, address, including zip code, and telephone number, including area code, of Agent for Service) ------------------------ COPY TO: DAVID E. REDLICK, ESQ. HALE AND DORR LLP 60 STATE STREET BOSTON, MASSACHUSETTS 02109 TELEPHONE: (617) 526-6000 ------------------------ - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- EXPLANATORY NOTE Pursuant to a Registration Statement (the "Registration Statement") on Form S-3 (File No. 333-33770), Millennium Pharmaceuticals, Inc. (the "Registrant") registered shares of its common stock, $.001 par value per share ("Common Stock"), under the Securities Act of 1933, as amended, all of which shares have been, to the Company's knowledge, sold as of the date hereof. Pursuant to the Registrant's undertaking contained in the Registration Statement, this Post-Effective Amendment No. 1 to Registration Statement on Form S-3 is being filed solely to remove from registration any shares of Common Stock which remain unsold under such Registration Statement as of the date of this Post-Effective Amendment No. 1. SIGNATURES Pursuant to Rule 478 promulgated under the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets the requirements for filing on Form S-3 and has duly caused this Post-Effective Amendment No. 1 to Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on this 2nd day of October, 2000. MILLENNIUM PHARMACEUTICALS, INC. By: /s/ JOHN B. DOUGLAS III ----------------------------------------- JOHN B. DOUGLAS III Senior Vice President and General Counsel 2