EXHIBIT 23.1

                         CONSENT OF INDEPENDENT AUDITORS

      We consent to the incorporation by reference in the Registration
Statements (Form S-3 No. 333-51772 and Form S-8 Nos. 333-82221, 333-19915,
333-19917, 333-59910 and 333-104820) of Transkaryotic Therapies, Inc. and in the
related Prospectuses of our report dated March 4, 2004, with respect to the
consolidated financial statements of Transkaryotic Therapies, Inc. included in
the Annual Report (Form 10-K) for the year ended December 31, 2003.

                                     /s/ Ernst & Young LLP

Boston, Massachusetts
March 9, 2004