The comparative study of the efficiency of using erythromycin and the combination of recombinant alpha 2-interferon with complex immunoglobulin preparation (CTP) for the treatment of chlamydiosis in pregnant women was made. 31 patients (group 1) received erythromycin orally in doses of 500 mg twice a day for 15-14 days. 30 other pregnant women were prescribed vaginal suppositories containing 300 mg. Of CTP, 2.0 x 10(6) I.U. of recombinant alpha 2-interferon and the intravaginal application of 15(2)-30 ml of solution containing the analogous amount of CTP and recombinant alpha 2-interferon. Immediately after treatment 7 patients with clinical signs of chlamydiosis were found in group 1 and 3 such patients, in group 2. In the pregnant women of group 1 the laboratory confirmation of chlamydial infection after treatment occurred 5.8 times more frequently than in the patients of group 2. In 7 women of group 1 vaginal candidiasis was diagnosed after treatment. In no case any side effects resulting from the proposed treatment were observed. Pathology caused by chlamydiae was shown to be absent in newborns and in parturient women who had received complex treatment for chlamydiosis.