Various immunoserologic and cellular immunity techniques have been used to explore the presence of antisperm antibodies in the serum and seminal plasma of male patients and in the blood and genital fluid of infertile women. Several recent comparative investigations using various assays to detect and quantitate levels of antibody to human spermatozoa have produced widely varying results. So the first WHO workshop on iso- and autonatibodies to human spermatozoa in 1974 tried to establish some unification in the techniques used. The purpose of this study is to compare the results of two methods-the Kibrick macro-agglutination test and the Isojima micro-immobilization test-using the same test materials based on recommandation from WHO workshop. The results are as follows: 1. Twenty normal controls showed negative reactions in all the 2 tests. Out of 25 patients, the positive sera were noted in 15 (60%) on the Kibrick test and 13 (51%) on the Isojima test. 2. Twelve (48%) out of 25 patients showed positive reactions in the two tests, and 16 (64%) out of 25 patients showed positive reaction in one or more tests. 3. The titers of the antisperm antibodies on the Kibrick test was higher than that on the Isojima test. Therefore, it seems to be possible to increase the chances of detection of the antisperm antibodies, if two tests are imployed.