The article presents the literature data on the incidence, the main clinical manifestations, modern methods for early neonatal and postnatal diagnosis and treatment of ventricular septal defect in children, as well as the prognosis of this disease. According to the International Classification of Diseases, 10th revision, ventricular septal defect is classified as Q21.0 Ventricular septal defect. Incidence. In the overall structure of congenital malformations of the cardiovascular system, ventricular septal defect has about 20 %. Diagnosis. Moderate ventricular septal defect is manifested by shortness of breath, rapid fatigability during feeding, delay in physical development. Significant arterial-venous shunt in the first month of life is accompanied by a transient mild cyanosis when the baby is fed and cries. Infants develop high pulmonary hypertension, circulatory failure, malnutrition. Small noise intensity is typical for newborns in the first weeks or even months of life, which is due to physiologically increased intravascular pulmonary resistance. Systolic murmur is extended to the entire systole with maximum amplitude at the left edge of the sternum at the level of III–IV intercostal spaces. Sclerotic phase of pulmonary hypertension with ventricular septal defect is defined as Eisenmenger reaction. The clinical picture of this disorder depends on the degree of hemodynamic instability caused by the defect parameters, the pressure level in the pulmonary artery, vascular pulmonary resistance, the magnitude and direction of the shunt through the defect. Diagnosis is confirmed by characteristic changes in the electrocardiogram, echocardiography and chest radiograph. Treatment. Small muscular ventricular septal defects often close spontaneously during the first 2 years of life. Drug correction is needed in the development of congestive heart failure. The optimum age for surgery — 5–9 years.