The purpose of the work was to determine the role of contaminated environment by U. diversum as a source of infections of the reproductive tract in cattle. It has been found that the period of Ureaplasma microorganisms survival outside the animals is relatively short, i.e. within 24 hours limits. However, it is long enough to make passible infection of the preputial mucosa of bulls. In contrast, heifers are rare infected under those conditions. Carries of U. diversum play an important role in the infection; their faeces sustain a permanent infection of environment. It constitutes a source of infection for animals free from infection. For prophylactic purposes one should take into account the need of carries removal by use of chemotherapeutics. Besides, an important role plays hygiene of cowsheds.