UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

        ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2001

OR

        TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934

Commission file number: 0-12042

BIOGEN, INC.

(Exact name of Registrant as specified in its charter)

Massachusetts
(State or other jurisdiction
of incorporation or organization) 04-3002117
(I.R.S. Employer
Identification No.)

14 Cambridge Center, Cambridge, Massachusetts 02142
(Address of principal executive offices) (zip code)

Registrant’s telephone number, including area code: (617) 679-2000

Securities registered pursuant to Section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act:
Common Stock, $.01 par value
(Title of class)

         Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Yes         No        

         Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of Registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.       

         Aggregate market value of Common Stock held by non-affiliates of the Registrant at March 26, 2002 (excludes shares held by affiliates): $7,324,113,016. Exclusion of shares held by any person should not be construed to indicate that such person possesses the power, direct or indirect, to direct or cause the direction of management or policies of the Registrant, or that such person is controlled by or under common control with the Registrant. Common Stock outstanding at March 26, 2002: 148,511,993 shares.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant’s definitive Proxy Statement for its 2002 Annual Meeting of Stockholders are incorporated by reference into Part III of this Report, and portions of the Registrant’s 2001 Annual Report to Shareholders are incorporated by reference into Parts II and IV of this Report.

         This form 10-K/A amends the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2001 to add as exhibits to the Form 10-K the financial statements for the Biogen Savings Plan and the related independent accountants’ consent.

         PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K

         (3)  Exhibits

The following documents are added as exhibits to the Form 10-K:

EXHIBIT NO.	DESCRIPTION
(23)	Consent of PricewaterhouseCoopers LLP
(99.1)	Financial Statements for Biogen Savings Plan

         Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

BIOGEN, INC.
By:	/s/ Peter N. Kellogg Peter N. Kellogg Executive Vice President – Finance and Chief Financial Officer

Dated June 28, 2002