GTC BIOTHERAPEUTICS TO HOST SECOND QUARTER 2009 EARNINGS CALL AND WEBCAST ON FRIDAY, JULY 31, 2009

Framingham, Mass., July 24, 2009-- GTC Biotherapeutics, Inc. (Nasdaq: GTCB) (“GTC”) announced today that its financial results for the second quarter 2009 will be released on Friday, July 31, 2009 followed by a webcast conference call starting at 10:00 a.m. Eastern Time. You may access the live internet broadcast or the subsequent archived recording, on GTC’s website at http://www.gtc-bio.com or access the conference call as follows:

Live Call – In the United States, dial 1-877-407-0778
Outside the United States, dial 201-689-8565

Audio Archive – In the United States, dial 1-877-660-6853
Outside the United States, dial 201-612-7415
Reference call ID: Account #: 286 Conference ID #: 328989

NOTE: a replay of the call will be available one hour following the end of the call and will be accessible until August 12, 2009 at 11:59 PM.

GTC Biotherapeutics develops, supplies and commercializes therapeutic proteins produced through transgenic animal technology. ATryn®, GTC’s recombinant human antithrombin, has been approved for use in the United States and Europe. ATryn is the first and only product produced in transgenic animals to be approved for therapeutic use anywhere in the world. In addition to ATryn, GTC is developing a portfolio of recombinant human plasma proteins with known therapeutic properties. These proteins include recombinant forms of human coagulation factors VIIa and IX, which are being developed for the treatment of hemophilia. GTC is also developing a portfolio of follow-on biologic monoclonal antibodies and a CD20 antibody with enhanced ADCC (antibody-dependent cell-mediated cytotoxicity). GTC’s intellectual property includes a patent in the United States through 2021 for the production of any therapeutic protein in the milk of any transgenic mammal. GTC’s transgenic production platform is particularly well suited to enabling cost effective development of proteins that are difficult to express in traditional recombinant production systems as well as proteins that are required in large volumes. Additional information is available on the GTC web site, http://www.gtc-bio.com.