About This Report

Biogen Idec’s second annual Corporate Citizenship Report presents our journey toward sustainability to our employees and key stakeholders. This report was prepared in accordance with the Global Reporting Initiative (GRI) G3 Guidelines.

Data in this report covers calendar years 2007 through 2010, with an emphasis on 2010 activities. All references to currency are in United States dollars. Biogen Idec is responsible for the preparation and integrity of the content in this report. Through a system of internal controls, including a comprehensive verification process by internal subject matter experts, we believe this report accurately represents our corporate citizenship initiatives.

Throughout this report, “Biogen Idec,” “we,” “us” and “our” refer to Biogen Idec and its consolidated subsidiaries; “RITUXAN” refers to both RITUXAN (the trade name for rituximab in the United States, Canada and Japan) and MabThera (the trade name for rituximab outside the United States, Canada and Japan). AVONEX® and RITUXAN® are registered trademarks of Biogen Idec or its subsidiaries. TYSABRI® is a registered trademark of Elan Pharmaceuticals, Inc., in the United States and of Elan Pharma International Ltd. in various countries outside the United States.