Between 1970 and 1978 135 infants with congenital malformations underwent operations due to congestive heart failure, progressive pulmonary hypertension, and severe cyanosis. Of them, 63% were acyanotic; 68% of all operations became necessary during the first 6 months of life. The late mortality rate was 5% and the hospital mortality rate 17%. A remarkably higher operative risk was found during the first 6 months of life. Ligation of patent ductus arteriosus as the most common lesion was done with a mortality rate of 2.5% which is comparable to the risk of late repair in childhood. Pulmonary artery banding could be performed in all acyanotic malformations with a mortality rate of 17% and of 12.5% in isolated VSD (including debanding and VSD closure in several cases). Coarctation of the aorta was corrected with a overall mortality rate of 26%. Because of a recurrence rate of 20%, the authors think that operations are only indicated in symptomatic cases of coarctation. In complex cyanotic malformations, a higher operative risk was observed in both pulmonary artery banding (38%) and shunt operations (44%). If surgical treatment is necessary, the earlier, the better.