Background. To date, there are no clear recommendations for the physical rehabilitation of children with congenital heart defects (CHD) after surgical correction. Until recently, the focus was on aerobic dynamic endurance exercise in patients with CHD, with intensity determined by peak oxygen consumption (VO2peak). The importance of strength training aimed at strengthening the musculoskeletal system has been less studied and is often overlooked, despite the fact that the amount of muscle strength determined using a wrist dynamometer is a predictor of the severity of the disease in patients with CHD.Objective. To evaluate the effectiveness and safety of strength training in a comprehensive rehabilitation program for children after radical treatment of congenital heart defects. Materials and methods. The clinical status of all patients was analyzed, physical examination, echocardiography (EchoCG), daily monitoring of the electrocardiogram (SMECG), cardiopulmonary exercise testing were performed, grip strength of both hands was measured using a wrist dynamometer, the strength of the muscles straightening the trunk was determined using a standing dynamometer. All participants were randomized into two groups. The first (control) group included patients who underwent early physical rehabilitation 3 months after the radical correction of CHD, which consisted of using only aerobic dynamic physical training. The second (main) group consisted of patients who were recommended a combined workout – aerobic dynamic load with strength exercises with weights, individually selected on the basis of wrist dynamometry. All measurements were collected at the beginning of the program and after its completion.Results. When analyzing the muscle strength estimated using a wrist dynamometer, it turned out that 36 (94.7 %) children showed a decrease in the strength index. There were no intergroup differences in the severity of muscle strength in the compared groups. In patients with CHD, the use of inpatient rehabilitation for 2 weeks and outpatient rehabilitation for 12 weeks, a combination of aerobic dynamic loads with strength training with weights individually calculated for each child led to a more pronounced increase in hand compression strength (p = 0.03) and trunk muscle strength (p = 0.04), estimated using functional testing. When comparing the spiroveloergometry data, children who were engaged in combined physical training showed higher performance compared to children who did not perform strength training. In addition, they demonstrated higher levels of transferable power during physical exertion.Conclusion. The use of combined aerobic dynamic loads with strength training with individually calculated weights during two weeks of inpatient and twelve weeks of outpatient rehabilitation led to a more pronounced increase not only in muscle strength, estimated using functional testing, but also increased the physical performance of children with corrected congenital heart defects in comparison with children who performed only dynamic aerobic loads.