Sec Form 4 Filing - HANNA NABIL @ BIOGEN IDEC INC - 2004-04-05

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 HANNA NABIL 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 Discovery Research (Last) (First) (Middle) 3030 CALLAN RD 3. Date of Earliest Transaction (MM/DD/YY) 04/05/2004 (Street) SAN DIEGO, CA92121 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 03/31/2004 J( 1 ) 615.9 A $ 31.399 450,904.9 D Common Stock 04/01/2004 M 25,000 A $ 0.5 475,904.9 D Common Stock 04/01/2004 S( 2 ) 25,000 D $ 55.31 450,904.9 D Common Stock 04/01/2004 M 20,551 A $ 0.5 471,455.9 D Common Stock 04/01/2004 S( 2 ) 20,551 D $ 55.25 450,904.9 D Common Stock 04/01/2004 M 8,921 A $ 0.5 459,825.9 D Common Stock 04/01/2004 S( 2 ) 8,921 D $ 55.1 450,904.9 D Common Stock 04/01/2004 M 16,079 A $ 0.4271 466,983.9 D Common Stock 04/01/2004 S( 2 ) 16,079 D $ 55.1 450,904.9 D Common Stock 04/01/2004 M 34,449 A $ 0.4271 485,353.9 D Common Stock 04/01/2004 S( 2 ) 34,449 D $ 55.25 450,904.9 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 Incentive Stock Option (right to buy) ( 3 ) $ 0.4271 04/01/2004 M 16,079 ( 4 ) 01/24/2005 Common Stock 16,079 ( 3 ) 55,921 D Incentive Stock Option (right to buy) ( 3 ) $ 0.4271 04/01/2004 M 34,449 ( 4 ) 01/24/2005 Common Stock 34,449 ( 3 ) 21,472 D Incentive Stock Option (right to buy) ( 3 ) $ 0.5 04/01/2004 M 25,000 ( 5 ) 09/12/2004 Common Stock 25,000 ( 3 ) 77,068 D Incentive Stock Option (right to buy) ( 3 ) $ 0.5 04/01/2004 M 20,551 ( 5 ) 09/12/2004 Common Stock 20,551 ( 3 ) 56,517 D Incentive Stock Option (right to buy) ( 3 ) $ 0.5 04/01/2004 M 8,921 ( 5 ) 09/12/2004 Common Stock 8,921 ( 3 ) 47,596 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HANNA NABIL 3030 CALLAN RD SAN DIEGO, CA92121 EVP Discovery Research Signatures By: Benjamin S. Harshbarger For: Nabil Hanna 04/05/2004 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Acquisition of shares under the Employee Stock Purchase Plan in a transaction exempt under SEC Rule 16b-3(c). ( 2 )Represents sale by Nabil Hanna pursuant to a qualified written selling plan under SEC rule 10b5-1. ( 3 )Granted under Issuer's Employee Stock Option Plan, in an exempt transaction under SEC rule 16b-3(d). ( 4 )Option becomes exercisable as to 25% of the optioned shares on 1/25/96 and as to the balance of the shares in 36 equal monthly installments thereafter. ( 5 )Option becomes exercisable for 25% of the optioned shares on 9/13/95 and as to the balance of the optioned shares in 36 equal monthly installments thereafter, subject to acceleration in the event the Issuer was to achieve a designated milestone.

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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