Objective. To study disturbances of sleep and circadian rhythms in patients with cardiovascular diseases taking into account the level of melatonin secretion and to optimize a complex approach to their treatment. Materials and methods. The study included patients with cardiovascular diseases with- (n=121) and without (n=105) cerebrovascular diseases (CVD). All patients received melaxen in dose 3 mg daily 30—40 min before sleep. Examination of patients included assessment of neurological status, psychometric scales, the definition of circadian rhythm of the heart and blood pressure, determination of 6-SOMT in daily urine. Results. Pathological changes in circadian rhythms affected sleep disturbances, emotional and cognitive disorders and were associated with a reduction in the level of 6-SOMT in the urine. These changes were most pronounced in patients with CVD and stroke. The inclusion of melaxen in the comprehensive regimen of treatment improved sleep, reduced mood disorders and normalized the circadian heart rate profile and blood pressure. Conclusion. The data obtained allowed to consider melaxen as an effective tool in the complex therapy of patients with CVD.