BACKGROUND One of every four Polish married couples is infertile. Numerous factors may contribute to the lack of conception in these couples, one of which may be the presence of antisperm antibodies in semen, cervical mucus and serum in infertile individuals. Thus immunological examinations of these individuals should be standard diagnostic practice. In the present paper we studied the frequency of antisperm antibodies among infertile Polish couples. METHODS Serum samples from infertile women (n=194) and men (n=186) were tested by means of the indirect immunobead-binding test. Also, cervical mucus samples obtained from 155 women were investigated using the same test. Semen samples from 202 men were tested with the direct immunobead-binding test. RESULTS 4.1% of the serum samples from infertile women were positive for antisperm antibodies, as well as 7% of the serum samples from infertile men, and 3.2% of the cervical mucus samples. 10.4% of the samples had spermatozoa-coated antibodies. In the respective control samples, the immunobead-binding test did not reveal any positive cases when given the applied 'cut-off' values. CONCLUSIONS This preliminary report attempts to determine for the first time the frequency of antisperm antibodies in a Polish population of infertile married couples.