Circulating antisperm antibodies (ASA) and immunosuppressive material in seminal plasma (SPIM) were determined by solid-phase enzyme staining method and anticomplement test respectively in 686 patients with abortion, including 285 couples. 241 fertile couples served as control. It revealed that the positive rate of ASA in repeatedly aborting patients was significantly higher than that in fertile controls (P less than 0.001). ASA was also more frequently detected in repeatedly aborting patients than in those having 1-2 abortion. Male partners whose wives aborted 2-6 times had significantly less SPIM than the controls with sperm count and sperm motility also markedly decreased. Meanwhile, the incidence of pyosemia was remarkably higher than that in the controls. It is suggested that ASA and SPIM play an important role in the development of recurrent abortions.