Vasectomized men with sperm auto-antibodies (S.A.A.) and high frequency of HLA-A20 antigen (Ag) were observed by Law et al. (1979); Hancock et al. (1983) observed the prevalence of HLA-A28 in infertile men with S.A.A. HLA-A, B and DR Ag were determined in a population of 80 Caucasian infertile men with (n = 22) or without (n = 58) agglutinating and/or cytotoxic S.A.A. in serum (S) and/or seminal plasma (SP), and the association between HLA-determinants and infertility with S.A.A. was investigated. The frequence of HLA-A28 Ag was found higher in the group with S.A.A. than without (18.2% vs 0.0%) but not statistically significant (chi 2 = 8.87; pc less than 0.15). The same result was obtained with HLA-B13 Ag (chi 2 = 8.87; pc less than 0.32). Lastly, there was no prevalence of HLA-DR Ag in men with S.A.A. In conclusion, no association was found between HLA-A, B and DR Ag and infertility with S.A.A. Nevertheless, two HLA-Ag were more frequently observed in the group with S.A.A.