SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): February 1, 2011
Biogen Idec Inc.
(Exact name of registrant as specified in its charter)
|(State or other jurisdiction
|133 Boston Post Road, Weston, Massachusetts
|(Address of principal executive offices)
Registrants telephone number, including area code: (781) 464-2000
(Former name or former address, if changed since last report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the
filing obligation of the registrant under any of the following provisions (see General Instruction
o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
Item 2.02 Results of Operations and Financial Condition.
On February 1, 2011, Biogen Idec Inc. issued a press release announcing its results of
operations and financial condition for the full year and three months ended December 31, 2010. A
copy of the press release is furnished as Exhibit 99 and is incorporated herein by reference.
The press release is being furnished pursuant to Item 2.02 of this Current Report on Form 8-K
and shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934
(the Exchange Act) or otherwise subject to the liabilities of that Section, nor shall such
document be deemed incorporated by reference in any filing under the Securities Act of 1933 or the
Item 9.01 Financial Statements and Exhibits.
The exhibits listed on the Exhibit Index immediately preceding such exhibits are furnished as
part of this Current Report on Form 8-K.