Objective. To assess and analyze the results of 6-68-month treatment with dienogest 2 mg in patients with adenomyosis. Subjects and methods. Sixty-two reproductive-aged patients diagnosed with adenomyosis received therapy with dienogest 2 mg for 6 months, of whom 24.2% continued to take the drug for a longer period. Results. Diffuse adenomyosis was observed in most (87.1%) patients; focal or nodular adenomyosis was seen in 24.2% of patients. During a 6-month dienogest treatment cycle, 53.4% of patients showed a decrease in pain intensity, 31 % had complete pain relief; 70.7% of patients had significant uterine volume reduction. All the patients were noted to have a decrease in the intensity, frequency, and duration of bloody vaginal discharge. Conclusion. The authors' own studies have established that the use of dienogest eliminates pain and abnormal uterine bleeding and decreases uterine volume in most patients. The therapy is characterized by good tolerance and can be used for a long time.