Two hundred nine children with congenital heart defects characterized by excessive pulmonary blood flow underwent pulmonary artery banding at The Hospital for Sick Children from January, 1972, through December, 1982. The indications for banding, rather than complete repair, varied with the type of cardiac defect as well as with the year of presentation to our hospital. A simplified method of estimating required band circumference has been developed for infants with ventricular septal defect, with or without major intracardiac mixing disorders. Infants with simple defects without intracardiac bidirectional mixing disorders receive a band at a circumference of 20 mm + 1 mm for each kilogram of body weight, whereas infants with bidirectional mixing disorders receive a band at a circumference of 24 mm + 1 mm for each kilogram of body weight. The overall operative mortality varies with the underlying cardiac defect and with associated medical conditions but is relatively low in the less-complicated cases. The use of a formula to predict a starting band circumference, with loosening only as required by cyanosis or bradycardia, allows predictable control of congestive symptoms and pulmonary hypertension in the majority of infants. The cumbersome measurement of pulmonary artery pressure and the unpredictable changes in pressure during anesthesia are avoided. Pulmonary artery banding remains an effective means of achieving satisfactory palliation in infants with congenital heart disease and excessive pulmonary blood flow.