Objective — clinical and laboratory evaluation of protective effect of remote ischemic preconditioning on myocardial state in children operated under CPB. Material and methods. We prospectively collected data of 33 patients with BSA 0.39±0.067 m2 aged 278 (100—1433) days. Anatomical diagnosis: Fallot's tetrad (n=18), total atrioventricular open channel (n=13) and a combination of these defects (n=2). Conditions of operation: CPB 140±20.4 minutes, aortic cross-clamping 98±14.6 minutes, crystalloid cardioplegia. Remote ischemic preconditioning procedure: simultaneous induction of both lower extremities ischemia with cuffs and duration of 5 minutes with 5-minutes reperfusion; threefold cycle repetition. Main group: 13 (39.4%) patients, who underwent remote ischemic preconditioning after induction of anesthesia. Control group: 20 patients operated without preconditioning. Biochemical markers of myocardial damage (TnI, CK-MB, myoglobin) were evaluated before remote ischemic preconditioning and within 24 hours after surgery. In the control points including admission into intensive care unit (ICU), 6 and 24 hours after the operation venous pO2, sO2, lactate, and inotropic index were examined. Duration of mechanical ventilation and ICU-stay after surgery have been fixed. Results. The concentration of TnI, CK-MB and myoglobin did not differ between the groups preoperatively. Serum TnI (p=0.009), CK-MB (p=0.029) and myoglobin (p=0.004) were significantly lower in preconditioned patients within 24 hours after operation. There were no other statistically significant clinical and laboratory differences between the groups. Conclusion. Presented data demonstrate cardioprotective effect of remote ischemic preconditioning in children requiring cardiac surgery. The clinical significance of this observation requires further study.