Multiple in situ freezing of the rabbit testis has been shown to be an effective antigenic stimulus as evidenced from the production of tissue-specific antibodies against a testicular antigen. These antibodies reacted with isologous as well as autologous testicular extracts. Histologic studies of testicular biopsies of the contralateral testis of frozen animals revealed alterations similar to those described by others following the induction of experimental autoimmune aspermatogenic orchitis by parenteral administration of testicular extracts in other species. The possibility of the induction of controlled freezing injury of an organ may provide a useful experimental model for further studies of autoimmunity in man and in experimental animals.