Previous studies have indicated that immunological factor is responsible for the infertility. We have detected sperm antibodies in ZIFT patients which grouped as fertilization failure (A; n=18) and low fertilization rate (${leq}50%$)(B; n=20). Patients, however, had normal oocytes and sperms. We collected serum from wives and semen from husbands and donors (fertile sperm), if it was needed. We examined class, binding patterns and amounts of antisperm antibodies(ASA) by direct and indirect immunobead binding assay. In group A, 11 husbands were ASA positive showing 62.2% and 61.1% binding with IgA and IgG, respectively, and two wives were ASA positive showing 70.0% and 71.0% binding with IgA and IgG, respectively. Binding sites were mainly at the head of sperms (84%). In group B, 8 husbands were ASA positive showing 37.5% and 40.0% binding with IgA and IgG, respectively, and two wives were ASA positive showing 41.3% and 42.0% binding with IgA and IgG, respectively. Binding sites were also mainly at the head of sperms (78%). For the treatment of ZIFT patients who had fertilization failure at the first trial, we used albumin fractionation method and dilution method with 30% fetal cord serum (FCS) to reduce the titer of ASA. We used partial zona dissection (P.Z.D.) method for wives who have antisperm antibodies in their serum. According to represented method, we could inhance the fertilization rate to 60.0% by albumin fractionation and 20.0% by P.Z.D., respectively. We concluded that the use of micromanipulation like P.Z.D. or the other sperm processing methods is required to increase a chance of fertilization. This result suggested that it should be a prerequisite to test antisperm antibodies prior to entering assisted reproductive technologies (ART) programs.