Clinical-instrumental examination and polysomnographic examination were performed in 56 patients with chronic cerebral ischemia on the background of venous cerebral dysfunction with concomitant pathology - chronic obstructive pulmonary disease. 21 (37.5%) of the examined patients had clinical manifestations of obstructive sleep apnea / hypopnea syndrome: mild - in 3, moderate - in 11, severe - in 7. A significant correlation was shown between body mass index, the number of episodes of apnea and the level of saturation of blood hemoglobin with oxygen, symptoms of venous cerebral dysfunction. Correlation with the index of forced expiratory volume for 1 second was not revealed. It should be assumed that in the pathogenesis of obstructive apnea / hypopnea syndrome in chronic obstructive pulmonary disease, the degree of obesity and venous cerebral dysfunction are more important than the severity of lower airway obstruction.