BIOGEN INC. — Director's Dealing 2012

Jan 9, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2012-01-06

Reporting Person: Rowinsky Eric K (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-01-06	Common Stock	M	1325	$59.82	Acquired	10460	Direct
2012-01-06	Common Stock	S	1325	$116.00	Disposed	9135	Direct
2012-01-06	Common Stock	M	11667	$59.82	Acquired	20802	Direct
2012-01-06	Common Stock	S	11667	$116.00	Disposed	9135	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-01-06	Stock Option (Right to Buy)	$59.82	M	1325	Disposed	2020-03-22	Common Stock (1325)	Direct
2012-01-06	Stock Option (Right to Buy)	$59.82	M	11667	Disposed	2020-03-22	Common Stock (11667)	Direct

Footnotes

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

F2: The stock options become exercisable in three (3) equal annual installments commencing one year after the grant date of 03/22/2010.