The morphology of the central pulmonary artery was studied by selective angiography in 21 previously unoperated patients (aged 11 days-21 years, median 4 years) with pulmonary atresia associated with various types of congenital heart disease. Angiographic findings were confirmed at operation in 10 patients. There was juxtaductal obstruction of the left pulmonary artery in two thirds of the patients with complete atresia in a quarter. Six of seven patients without juxtaductal obstruction had pulmonary valve atresia, but all nine patients with juxtaductal stenosis had truncal atresia. No patient had stenosis of the right pulmonary artery.