Objective — to estimate efficacy and safety of melatonin in REM-sleep behavior disorders (RBD) in patients with Parkinson’s disease (PD). Material and methods. We examined 60 patients with RBD and I—III stages of PD. Neuropsychological examination was performed before and after treatment. RBD was confirmed by polysomnography in 30 patients. Results. After the treatment with melatonin in dose of 3—6 mg for 4 weeks, 84% of patients reported reduction of RBD symptoms, daytime sleepiness, anxiety and depression. Conclusion. Melatonin can be used for RBD treatment in PD patients.