1 Exhibit 21 ---------- List of Subsidiaries -------------------- Name State or other ---- -------------- jurisdiction of --------------- organization ------------ Biogen Securities Corp. Massachusetts Biogen Realty Corp. Massachusetts Biogen GmbH Germany Biogen Limited United Kingdom Biogen France, S.A. France Biotech Manufacturing Ltd. Channel Islands Biogen B.V. The Netherlands Biogen Technologies, Inc. Delaware Biogen Canada, Inc. Delaware Biogen Marketing GmbH Switzerland