Sec Form 4 Filing - Kowolenko Michael @ BIOGEN IDEC INC. - 2007-07-25

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 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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1. Name and Address of Reporting Person Kowolenko Michael 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) SVP, Pharm Ops & Technology (Last) (First) (Middle) 14 CAMBRIDGE CENTER 3. Date of Earliest Transaction (MM/DD/YY) 07/25/2007 (Street) CAMBRIDGE, MA02142 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 07/25/2007 M( 1 ) 3,450 A $ 42.12 21,573.856 ( 2 ) D Common Stock 07/25/2007 M( 1 ) 4,356 A $ 37.45 25,929.856 D Common Stock 07/25/2007 M( 1 ) 8,438 A $ 43.5 34,367.856 D Common Stock 07/25/2007 M( 1 ) 4,263 A $ 44.24 38,630.856 D Common Stock 07/25/2007 S( 1 ) 20,507 D $ 58 18,123.856 D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Stock Option (Right to buy) $ 42.12 07/25/2007 M( 1 ) 3,450 ( 3 ) 04/01/2012 Common Stock 3,450 ( 4 ) 3,450 D Stock Option (Right to buy) $ 37.45 07/25/2007 M( 1 ) 4,356 ( 5 ) 12/06/2012 Common Stock 4,356 ( 4 ) 4,355 D Stock Option (Right to buy) $ 43.5 07/25/2007 M( 1 ) 8,438 ( 6 ) 02/06/2014 Common Stock 8,438 ( 4 ) 14,062 D Stock Option (Right to buy) $ 44.24 07/25/2007 M( 1 ) 4,263 ( 7 ) 02/06/2016 Common Stock 4,263 ( 4 ) 29,837 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Kowolenko Michael 14 CAMBRIDGE CENTER CAMBRIDGE, MA02142 SVP, Pharm Ops & Technology Signatures Robert A. Licht, Attorney in Fact for Michael Kowolenko 07/27/2007 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Exercise/sale pursuant to a trading plan intended to comply with Rule 10b5-1 of the Securities Exchange Act of 1934. ( 2 )Includes 117.9266 shares acquired on March 30, 2007 and 39.4994 shares acquired on June 29, 2007 under the Biogen Idec Inc. Employee Stock Purchase Plan. ( 3 )The stock option became exercisable in four (4) equal annual installments, commencing one year after the grant date of 04/01/02. ( 4 )Granted under one of the Issuer's stock option plans, in an exempt transaction under SEC rule 16(b)-3(d). ( 5 )The stock option became exercisable in four (4) equal annual installments, commencing one year after the grant date of 12/06/02. ( 6 )The stock options become exercisable in four (4) equal annual installments on 12/31/04, 12/31/05, 12/31/06 and 12/31/07. ( 7 )The stock option becomes exercisable in four (4) equal annual installments, commencing one year after the grant date of 02/06/06.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* 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).

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