Congenital heart lesions are found in 0.8% of all newborns; four-fifths of them are correctable. Two thirds of all surgical procedures are done in acyanotic malformations, mainly in septal defects, patent ductus arteriosus, coarctations of the aorta and valvular stenosis. Within the last twenty years corrective repair has been established with good results in these lesions. Therapeutic problems still remain in cases of late diagnosis and in some rare and complex anomalies like malformations of the aortic arch, of the coronary arteries, in some types of aortopulmonary window and atrioventricular canal. Surgery becomes urgent in babies suffering from severe heart disease because of progressive pulmonary hypertension, inadequate growth or severe heart failure (despite intensive medical treatment). For certain lesions corrective repair (patent ductus arteriosus, coarctation) is definitely indicated, for others (ventricular septal defect, atrioventricular canal) urgent palliation or early total repair is debatable. In most patients with uncomplicated lesions treated in time during childhood a low operative mortality below 1% was observed. A higher mortality rate was found (10 to 50%) in patients with pulmonary artery disease or associated pulmonary lesions. A significantly higher mortality could also be observed in the advanced age group (4.7%) and in infants below one year of age (11,5%), underlining the important point of the age at operations. Recurrence of lesions occured in 1% of our patients after closure of ventricular septal defects, reconstructions of mitral valve disease and early corrected coarctations. Nevertheless, most of these patients can expect a normal growth, life span and ability to work.