Operations were performed on 117 patients with congenital pulmonary stenosis or atresia. Diagnosis in the patient with a typical tetralogy of Fallot is not difficult. Variations from this typical picture, noted on physical examination, roentgenogram and fluoroscopy, are discussed. Six patients with tricuspid atresia are reviewed with particular reference to differential diagnosis. One patient with pulmonary valve stenosis and a patent foramen ovale is presented. An aortic-pulmonary anastomosis was accomplished in 105 patients with 10 deaths, a mortality rate of 9.5%. Twelve patients were explored with a mortality of 50%. The over-all mortality was 13.8%. The causes of death are reviewed. Results have been slightly less satisfactory in older patients with a right aortic arch than in those patients with a left aortic arch. Excessive cardiac enlargement has occurred in a few instances.