In this study we have compared the results of autoagglutination, IgM M.A.R.-test, seric S.I.T. and seric T.A.T. in 75 men with normal seminal parameters belonging to sub-fertile couples in whom the only evident anomaly was the presence of negative or doubtful P.C.T. We compared a tight correlation between IgG M.A.R.-test and autoagglutination (IgG M.A.R.-test clinically positive in 82.8% of subjects with positive spermagglutination); between seric S.I.T. and IgG M.A.R.-test (S.I.T. positive in 58.3% of subjects with IgG M.A.R.-test clinically positive); between seric T.A.T. and IgM M.A.R.-test (T.A.T. positive in 69.4% of subjects with positive IgG M.A.R.-test). Such results proved the reliability of IgG M.A.R.-test as a screening test in the determination of male autoimmunization. Moreover, the possibility that they were the cases in which only the local antisperm activity was shown, underlines the necessity not to limit immunological research to only seric antibody titrations. The analyses of the types of mixed agglutination present in cases of positive IgG M.A.R.-test make us suspect that a quota of the agglutination type emh was due to the impossibility with such type of test to specify adequately the zones of G.R. sperm interaction involved in the formation of mixed agglutinates.