BIOGEN INC. — Director's Dealing 2012

May 4, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2012-05-03

Reporting Person: Cox John (EVP Pharmaceutical Oper & Tech)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-03	Common Stock	F	765	$134.26	Disposed	12178.4445	Direct

Footnotes

F1: Includes 230.415 shares acquired under the Biogen Idec Inc. employee stock purchase plan on 3/31/2012.