FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * SCHNEIER CRAIG ERIC   2. Issuer Name and Ticker or Trading Symbol BIOGEN IDEC INC. [BIIB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP, HR, Public Affairs & Comm (Last) (First) (Middle) BIOGEN IDEC INC., 133 BOSTON POST ROAD 3. Date of Earliest Transaction (Month/Day/Year) 02/23/2011 (Street) WESTON, MA 02493 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 02/23/2011   M   4,077 A $ 0 20,513.2794 D   Common Stock 02/23/2011   M   953 A $ 0 21,466.2794 D   Common Stock 02/23/2011   F   1,295 D $ 66.76 20,171.2794 D   Common Stock 02/23/2011   F   303 D $ 66.76 19,868.2794 D   Common Stock 02/25/2011   M(1)   9,725 A $ 49.31 29,593.2794 D   Common Stock 02/25/2011   S(1)   9,725 D $ 68.2 19,868.2794 D   Common Stock               460 I By Spouse

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stock Unit

$ 0 (2)

02/23/2011

M

4,077

(3)

02/23/2014

Common Stock

4,077

$ 0

20,381

D

Restricted Stock Unit

$ 0 (2)

02/23/2011

M

953

(3)

02/23/2014

Common Stock

953

$ 0

19,428

D

Restricted Stock Unit

$ 0 (2)

02/23/2011

J

1,086 (4)

(3)

02/23/2014

Common Stock

0

$ 0

18,342

D

Stock Option (Right to Buy) (5)

$ 49.31

02/25/2011

M(1)

9,725

(6)

02/11/2017

Common Stock

9,725

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
SCHNEIER CRAIG ERIC BIOGEN IDEC INC. 133 BOSTON POST ROAD WESTON, MA 02493			EVP, HR, Public Affairs & Comm

Signatures

Aras Lapinskas, Attorney in Fact for Craig E. Schneier		02/25/2011
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Exercise/sale pursuant to a trading plan intended to comply with Rule 10b5-1 of the Securities Exchange Act of 1934.
(2)	There is no conversion or exercise price for this stock unit.
(3)	The number of RSUs reported represents the maximum possible number of shares that are eligible for vesting, which is 150% of the number of shares at target payout. One-fourth of these RSUs are eligible to vest on each of the first four anniversaries of the grant date. The actual number of shares that will vest on each vesting date will be determined by comparing the price of Biogen Idec common stock on such vesting date to the price on the grant date (i.e., number of vested shares = number of shares at target payout times [the average 60 calendar-day closing stock price ending on the vesting date divided by the average 60 calendar-day closing stock price on the grant date]).
(4)	This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested.
(5)	Granted under one of the Issuer's stock option plans, in an exempt transaction under SEC rule 16(b)-3(d).
(6)	The stock option becomes exercisable in four (4) equal annual installments, commencing one year after the grant date of 02/12/07.

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