Authors report their observations obtained in the course of treatment of 36 patients suffered from pelvic Actinomycosis. The course of disease of patients treated with pelvic inflammatory disease during a period of five years was compared with the occurrence at IUD users and non-users. The interdependence of occurrence of Actinomycosis, as well as previous deliveries, abortions and the period of use of IUD was investigated retrospectively. Difference was made between primary and secondary Actinomycosis. Authors investigated the methods of diagnostics of Actinomycosis and those of prevention and treatment. It was stated that because of pelvic Actinomycosis at IUD users the surgical intervention was not higher than the PID caused by other pathogenic. microorganisms.