Exhibit 23.3

CONSENT OF INDEPENDENT AUDITORS


We consent to the reference to our firm under the caption "Experts" and to
the use of our report dated February 22, 2000, with respect to the financial
statements of GelTex Pharmaceuticals, Inc. incorporated by reference in
Amendment No. 2 to the Registration Statement (Form S-4 No. 333-34972) and
related Prospectus of Genzyme Corporation for the registration of shares of
its common stock.


/s/ Ernst & Young LLP


Boston, Massachusetts
October 23, 2000