Objective. To study the structure, risk factors and methods of prevention of postoperative brain dysfunction on the example of coronary artery bypass surgery with cardiopulmonary bypass. Material and methods. The study included 77 patients who undergone elective coronary artery bypass surgery at the beating heart (22 patients) or with cardiopulmonary bypass (55 patients, including 24 patients, who received cerebroprotective treatment with cytoflavin in the preoperative period). All patients underwent dynamic (pre- and postoperative) neurological, neuropsychological, instrumental examinations. Results. The postoperative cerebral dysfunction was diagnosed in 34 (44,2%) patients. The frequency of the clinical types of postoperative cerebral dysfunction significantly differed: perioperative stroke – 3 (3,9%) cases, symptomatic delirium of the early postoperative period – 11 (14,3%) cases, delayed cognitive impairment – 28 (36,4%) cases. The risk factors of postoperative cerebral dysfunction after the coronary artery bypass surgery with cardiopulmonary bypass were identified. Preventive preoperative use of the neuroprotective drug cytoflavin reduces the severity of delayed cognitive impairment after the coronary artery bypass surgery with cardiopulmonary bypass and has a good safety profile. Conclusion. An analysis of the literature data and the results of our own studies show that postoperative cerebral dysfunction is the nosological entity with various etiological factors, pathogenetic mechanisms and the characteristic clinical types, which has an effect on the outcome of surgical treatment.