The specifics of inflammation created by infection with Chlamydia trachomatis could be favourable to the genesis of endometriosis. To investigate this hypothesis, we studied the association between Chlamydia trachomatis specific IgG and IgA antibodies in serum and the peritoneal fluid of 51 women undergoing laparoscopic surgery. There was no significant difference between women with and without endometriosis with respect to the incidence of IgG and IgA in serum or the peritoneal fluid. The results of our preliminary study did not show any significant link between past infection with Chlamydia trachomatis and the presence of endometriosis.