We performed HLA typing in 96 couples affected by recurrent abortion "sine causa". We matched these patients with 124 fertile couples and 204 individuals random paired. No significant difference in HLA sharing was demonstrated in the three study groups. The statistical analysis denoted significant differences in regard to HLA A3, A24, B12, and DR- comparing patients and normal members of fertile couples. The frequencies of HLA Cw5, Cw6 and DR2 were different in patients when compared with their partners.