1 EXHIBIT 23 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 of Biogen Savings Plan of our report dated June 27, 2000 relating to the financial statements and supplemental schedules of the Biogen Savings Plan for the year ended December 31, 1999 included with this Form 10-K/A. PricewaterhouseCoopers LLP Boston, Massachusetts June 27, 2000