Exhibit 99.1



CONTACT:
Justine E. Koenigsberg
Director, Corporate Communications
(617) 349-0271

FOR IMMEDIATE RELEASE

           TKT ANNOUNCES EXERCISE OF OVERALLOTMENT OPTION

CAMBRIDGE, MA, DECEMBER 18, 2001-- Transkaryotic Therapies, Inc. (Nasdaq: TKTX)
today announced the completion of its previously announced follow-on public
offering, raising a total of $125,580,000. A total of 3,220,000 shares were sold
at $39.00 per share, including 420,000 shares to cover overallotments. The joint
bookrunning managers for the offering were SG Cowen Securities Corporation and
Deutsche Banc Alex. Brown. Co-managers of this offering were Pacific Growth
Equities, Inc. and Leerink Swann & Company.

Copies of the prospectus relating to this offering of common stock may be
obtained from SG Cowen Securiites Corporation through ADP by calling (631)
254-7106 or by fax at (631) 254-7140; Deutsche Banc Alex. Brown, Prospectus
Department, One South Street, Baltimore, MD 21202, (410) 895-2070, or from the
offices of any of the managing underwriters listed above.

A registration statement relating to these securities has been filed with and
declared effective by the Securities and Exchange Commission. This press release
shall not constitute an offer to sell or the solicitation of an offer to buy nor
shall there be any sale of these securities in any state in which such offer,
solicitation or sale would be unlawful prior to registration or qualification
under the securities laws of any such state.

ABOUT TKT
Transkaryotic Therapies, Inc. (TKT) is a biopharmaceutical company dedicated
to the development and commercialization of products based on its three
proprietary development platforms: Niche Protein(R) products,
Gene-Activated(R) proteins, and gene therapy. The Company's Niche Protein
product platform is based on protein replacement for the treatment of rare
genetic diseases, a group of disorders characterized by the absence of
certain metabolic enzymes. TKT's gene activation technology is a proprietary
approach to the large-scale production of therapeutic proteins, which does
not require the cloning of genes and their subsequent insertion into
non-human cell lines. The Company's gene therapy technology, known as
Transkaryotic Therapy(TM), is focused on the commercialization of non-viral,
EX VIVO gene therapy products for the long-term treatment of chronic protein
deficiency states.

GENE-ACTIVATED(R), NICHE PROTEIN(R), AND TKT(R) ARE REGISTERED TRADEMARKS AND
TRANSKARYOTIC THERAPY(TM) IS A TRADEMARK OF TRANSKARYOTIC THERAPIES, INC.

PLEASE VISIT OUR WEB SITE AT WWW.TKTX.COM FOR ADDITIONAL INFORMATION ABOUT
TRANSKARYOTIC THERAPIES, INC.
                                       ###