Between 1970 and 1981 we observed 26 children with pulmonary atresia and ventricular septal defect (PA-VSD). 24 patients had two pulmonary arteries with a bifurcation, one patient had only one central pulmonary artery and one patient had none. Patients in whom lung perfusion was carried out by the ductus arteriosus usually had well developed pulmonary arteries. Palliative surgery (aortopulmonary shunts, Brock procedure, right ventricular outflow tract patch without closure of the VSD) was performed in cases with hypoplastic pulmonary arteries. A comparison of pre- and postoperative angiocardiographies showed an improvement of pulmonary perfusion in all patients. In 3 of 8 children there was an increase in pulmonary artery diameter, which made them more suitable candidates for corrective surgery. Intrapulmonary stenoses and lung segments perfused exclusively by large systemicopulmonary collaterals made corrective surgery impossible in the other 5 children.