A total of 43 females including 13 with sterility, 23 with habitual miscarriage and 7 pregnant women with a history of chronic inflammatory diseases were examined by using various tools to detect their Mycoplasma and Ureaplasma infections. The females had been studied for bacterial and chlamydial infections. Forty of them turned out to be infected with M. hominis and U. urealyticum. In some cases, sanation led to the improvement of the patients' status, the occurrence of pregnancy, its favourable course and termination in subjects with sterility and habitual miscarriage. The value of the findings is discussed in the paper.