EXHIBIT 23.3



               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the reference to our firm under the caption "Experts" in the
Registration Statement (Form S-3) and related Prospectus of Genzyme
Corporation for the registration of 2,064,438 shares of Genzyme General
Division common stock and to the incorporation by reference therein of our
report dated February 22, 2000, with respect to the consolidated financial
statements of GelTex Pharmaceuticals, Inc. included in its Annual Report
(Form 10-K) for the year ended December 31, 1999, filed with the Securities
and Exchange Commission.

                                                           /s/ Ernst & Young LLP

Boston, Massachusetts
August 24, 2001