From 1956 through July 1981, 15 patients, ranging in age from 9 days to 20 years, underwent surgical correction of aortopulmonary (AP) window. Surface hypothermia and venous inflow occlusion were used in the first patient. In four patients, the technique for closure of AP window was similar to that for patent ductus arteriosus: in one, the AP window was ligated; and in three, clamping, division and suture were performed. Cardiopulmonary bypass was used in ten patients. In five patients, division and primary closure were done. In five, a patch was used to close the defect by using the transaortic and/or pulmonary approach. Associated cardiovascular anomalies were repaired concomitantly in four of seven patients. Two patients died during the immediate postoperative period; both were infants and had serious associated cardiovascular anomalies. One patient died from increased pulmonary vascular resistance and right heart failure 1 year after replacement of the tricuspid valve. Of 12 patients who survived the operation, 11 had excellent results. For the surgical treatment of patients with AP window, we stress the safety and ease afforded by extracorporeal circulation and a preference for the transaortic approach and fabric patch closure.