Two groups of adult Swiss mice were immunised with washed syngeneic spermatozoa without any adjuvant for a period of two months or four months respectively. The presence of antibodies to spermatozoa was measured by micro sperm-agglutination and micro sperm-immobilization tests. The development of cell mediated immune response (CMIR) was measured by leucocyte migration inhibition test (LMIT) using spermatozoal antigens solubilized by 3M KCl, Nonidet P-40 or by subjecting the cells to ultrasonication. SDS-PAGE analysis of these proteins indicated that extraction of spermatozoa with 3 M KCl was a better method for solubilization of antigens present on sperm membrane. Almost all immunized mice had varying titers of sperm agglutinating antibodies. Nearly 40-50 per cent of the mice had a titre of 1:128 in both groups whereas only 33 per cent had sperm immobilizing antibodies. CMIR, as assessed by LMIT, was detected in immunized mice. However, this had not resulted in the infiltration of immune cells into the target organs perhaps due to the lower magnitude of immune response.