BIOGEN INC. — Director's Dealing 2011

May 27, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2011-05-26

Reporting Person: PANGIA ROBERT W (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-05-26	Common Stock	M	10000	$68.15	Acquired	24080	Direct
2011-05-26	Common Stock	M	5000	$34.34	Acquired	29080	Direct
2011-05-26	Common Stock	S	12800	$93.0436	Disposed	16280	Direct
2011-05-26	Common Stock	S	2200	$93.495	Disposed	14080	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-05-26	Stock Option (Right to Buy)	$68.15	M	10000	Disposed	2012-01-01	Common Stock (10000)	Direct
2011-05-26	Stock Option (Right to Buy)	$34.34	M	5000	Disposed	2014-01-01	Common Stock (5000)	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: This represents the weighted average price for shares sold at a range between $92.42 (low) and $93.41 (high).

F3: Full information regarding the number of shares sold at each separate price will be provided upon request by the SEC staff, the issuer, or a security holder of the issuer.

F4: This represents the weighted average price for shares sold at a range between $93.43 (low) and $93.59 (high).