Objective: A contribution to the role of Chlamydophila pneumoniae in women from the IVF program. Design: A serological study proving the antibodies against the antigens of Chlamydophila pneumoniae (C. pneumoniae) and Chlamydia trachomatis (C. trachomatis) in women from the IVF program suffering from different factor of infertility. Setting: Veterinary Research Institute, Brno. Methods: The complement fi xation test with chlamydial antigen and ELISA tests proving IgA and IgG antibodies against genus-specifi c antigen (cLPS) and species-specifi c chlamydial major outer membrane protein (cMOMP) of C. trachomatis and C. pneumoniae in the blood serum of 32 females being in the fertilization program due the tubal factor infertility have been estimated and the results compared with those obtained in 26 females being in the fertilization program due the ovarian factor and in 42 female with andrological factor, respectively. Results: The frequency of positive complement fi xation test proved in the group of women with tubal factor infertility was signifi cantly higher than in the groups with ovarial and andrological factor, respectively. The number of the strongly positive reactions (with high titres) in the group with tubal factor infertility was higher than in two remaining groups. The occurrence of species- -specifi c IgG antibodies (anti-C. trachomatis) and chlamydia genus-specifi c IgA antibodies proved by means of ELISA in the group with tubal factor was statistically more frequent. The difference of the species-specifi c anti-C. pneumoniae antibodies in all three groups examined was not signifi - cant. The simultaneous occurrence of species-specifi c antibodies against anti-C. pneumoniae and C. trachomatis in the group with tubal factor was higher than in other groups (in comparing with the group with andrological factor statistically signifi cant). Conclusion: The opinion of the authors being in agreement with the view of most specialists is that the most important agent in the pathogenesis of tubal factor fertility is C. trachomatis. C. pneumoniae is above all a respiratory pathogen with a high prevalence and its impact for fertility disorders may be in the synergismus with C. trachomatis. The serological examination of both chlamydial infections should be a standard part of diagnostic algorithm.

        Key words: antibodies against C. trachomatis and C. pneumoniae, tubal, ovarian and andrological factors fertility disorders