BIOGEN IDEC TO REPORT THIRD QUARTER 2012 FINANCIAL RESULTS ON OCTOBER 25, 2012

Biogen Idec Inc. today announced it will report third quarter 2012 financial results on Thursday, October 25, 2012, before the financial markets open.

Following the release of the financials, the Company will host a live webcast where Biogen Idec management will discuss the financial results, at 8:00 am ET. To access the live webcast, please go to the investor relations section of Biogen Idec’s website at www.biogenidec.com. Following the live webcast, an archived version of the call will be available at the same URL, for one month.

About Biogen Idec

Through cutting-edge science and medicine, Biogen Idec discovers, develops and delivers to patients worldwide innovative therapies for the treatment of neurodegenerative diseases, hemophilia and autoimmune disorders. Founded in 1978, Biogen Idec is the world’s oldest independent biotechnology company. Patients worldwide benefit from its leading multiple sclerosis therapies, and the company generates more than $5 billion in annual revenues. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com.