BIOGEN INC. — Director's Dealing 2011

Mar 3, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2011-03-02

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-03-02	Common Stock	S	100	$69.02	Disposed	10788	Direct
2011-03-02	Common Stock	S	586	$70.1734	Disposed	10202	Direct
2011-03-02	Common Stock	S	616	$69.9816	Disposed	9586	Direct
2011-03-02	Common Stock	S	100	$70.32	Disposed	9486	Direct

Footnotes

F1: 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 $70.03 (low) and $70.33 (high).

F3: This represents the weighted average price for shares sold at a range between $69.31 (low) and $70.26 (high).

F4: 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.