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Prospectus Supplement                          Filed Pursuant to Rule 424(b)(3)
To Prospectus Dated September 18, 1998               Registration No. 333-59513




                                    GENZYME
                                        
 $250,000,000 Principal Amount of 5 1/4% Convertible Subordinated Notes Due 2005
                                        
           6,313,131 Shares of Genzyme General Division Common Stock



     Genzyme previously issued $250,000,000 principal amount of 5 1/4%
convertible subordinated notes due 2005. Holders of these notes can convert
principal into shares of Genzyme General Division Common Stock. This prospectus
supplement relates to sales of these notes and such shares.

     A copy of the prospectus dated September 18, 1998 should be delivered to
you together with this prospectus supplement. In deciding whether to invest, you
should carefully review the information in the prospectus and this prospectus
supplement.

                          ___________________________

     INVESTING IN THE 5 1/4% CONVERTIBLE SUBORDINATED NOTES AND SHARES OF
GENZYME GENERAL DIVISION COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. YOU SHOULD
CAREFULLY READ AND CONSIDER THE "RISK FACTORS" BEGINNING ON PAGE 3 OF THE
PROSPECTUS.

                          ___________________________

     Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus supplement is truthful or complete. Any representation to the
contrary is a criminal offense.







          THE DATE OF THIS PROSPECTUS SUPPLEMENT IS JANUARY 26, 1999.



Genzyme Corporation - One Kendall Square, Cambridge, Massachusetts 02139 -
(617) 252-7500
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                            SELLING SECURITYHOLDERS

     The information in the following table is presented as of January 25, 1999
and supersedes in part the information in the table appearing under the heading
"Selling Securityholders" in the prospectus:



                          PRINCIPAL AMOUNT                 NUMBER OF SHARES
                              OF NOTES                       OF GGD STOCK+     NUMBER OF SHARES OF
                            BENEFICIALLY    PERCENTAGE OF    BENEFICIALLY       GGD STOCK+ ISSUABLE
                              OWNED THAT        NOTES       OWNED PRIOR TO    UPON CONVERSION OF THE
       NAME                  MAY BE SOLD     OUTSTANDING       OFFERING      NOTES THAT MAY BE SOLD(1)
       ----               ----------------  -------------  ----------------  -------------------------
                                                                 
Goldman, Sachs & Co......      450,000            *               0                   11,363

Lombard Odier & Cie......      100,000            *               0                    2,525

Warburg Dillon Read LLC..      250,000            *               0                    6,313

______________
+   Genzyme General Division Common Stock.
*   Less than 1%.
(1) Assumes conversion of the full amount of  notes held by such holder at the
    initial rate of 25.2525 shares of Genzyme General Division Common Stock per
    $1,000 in principal amount of the notes. The conversion rate and the number
    of shares of Genzyme General Division Common Stock issuable upon conversion
    of the notes may be adjusted under certain circumstances. See "DESCRIPTION
    OF NOTES -- Conversion Rights"  beginning on page 16 of the prospectus.
    Accordingly, the number of shares of Genzyme General Division Common Stock
    issuable upon conversion of the notes may increase or decrease from time to
    time. Under the terms of Genzyme's Indenture dated May 22, 1998, fractional
    shares will not be issued upon conversion of the notes; cash will be paid
    instead of fractional shares, if any.






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