Objective — to evaluate the efficacy and safety of therapy for normalization of menstrual cycle with micronized progesterone and preservation of the effects this therapy after stopping treatment. Subject and methods. In total, 776 women aged 18—40 years with an irregular menstrual cycle (lasting less than 24 days or more than 38 days) took part in the study for at least 3 months, who were prescribed micronized progesterone (Utrogestan) orally for therapy 200—400 mg per day for 10 days from 17 to 26 day of the menstrual cycle. The duration of treatment for each patient was up to 3 menstrual cycles, then the patients were observed for 3—6 menstrual cycles. During the study, demographic and anthropometric data, complaints, medical and obstetric and gynecological history were recorded, patients kept diaries to obtain information about the nature of the menstrual cycle in dynamics, the intensity of menstruation pain was assessed using an 11-point Likert scale, assessment of the overall satisfaction and clinical status of patients on a scale of general clinical impression, as well as assessment of psycho-emotional status in dynamics with the help of the hospital scale of anxiety and depression (HADS). Also recorded adverse events that occur during the entire period of treatment and observation. Results. The main criterion of effectiveness of the treatment was normalization of menstrual cycle (lasting 24—38 days), which was achieved in 98.3% of cases after the treatment. The achieved result remained at the level of 95.0% after 3 months and 97.9% after 6 months of observation after the end of treatment. The analysis of the identified adverse events showed a favorable safety profile of the treatment (quality and quantity of adverse events detected was comparable to the data described in the leaflet of Utrogestan). Conclusion. The study confirmed a sufficient profile of efficacy and safety of treatment of menstrual disorders (lasting less than 24 days or more than 38 days) with micronized progesterone in accordance with locally approved instructions for the medical use of Utrogestan — 200—400 mg per day within 10 days from 17 to 26 day of the menstrual cycle.