BIOGEN INC. - Director's Dealing 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2012-04-25

Reporting Person: ALEXANDER SUSAN H (EVP, General Counsel)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-04-25	Common Stock	M	16764	$44.73	Acquired	26949	Direct
2012-04-25	Common Stock	S	16764	$130.00	Disposed	10185	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-04-25	Stock Option (Right to Buy)	$44.73	M	16764	Disposed	2016-01-30	Common Stock (16764)	Direct

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

F2: Granted under one of the Issuer's stock option plans, in an exempt transaction under SEC rule 16(b)-3(d).

F3: The stock option becomes exercisable in four (4) equal annual installments, commencing one year after the grant date of 01/30/06.