BIOGEN INC. — Director's Dealing 2011

Oct 4, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2011-10-01

Reporting Person: Gagnon Robert E. (Chief Acct Officer VP & Contr)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-10-01	Common Stock	F	118	$93.15	Disposed	7635	Direct
2011-10-03	Common Stock	M	778	$49.59	Acquired	8413	Direct
2011-10-03	Common Stock	S	778	$92.55	Disposed	7635	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-10-03	Stock Option (Right to Buy)	$49.59	M	778	Disposed	2018-10-01	Common Stock (778)	Direct

Footnotes

F1: Exercise/sale pursuant to a trading plan intended to comply with Rule 10b5-1 of the Securities Exchange Act of 1934.

F2: The stock options become exercisable in four (4) equal annual installments commencing one year after the grant date of 10/01/2008.