Sixty-three patients who underwent banding of the pulmonary artery between 1968 and 1975 were studied. Mortality among patients who underwent the banding procedure was 22%, and among those with ventricular septal defect it was 7%. Thirty-eight of the 49 survivors of the banding procedure were investigated for abnormalities of the pulmonary outflow tract caused by the band. Seventy-one percent of these 38 patients had an identifiable abnormality of the pulmonary valve or artery. These complications occurred more frequently in patients banded at a very young age (less than 2 months old) and in patients in whom the band was in place more than two years. Corrective operations have been performed in 24 of the 49 patients who survived banding. Seventy-six percent of the patients with ventricular septal defect survived corrective operation, while only 29% of the patients with more complex lesions survived.