The late results of 70 patients aged 1.96 to 35.9 (mean 10.1) years who had repair of ventricular septal defect and aortic insufficiency from 1968 to 1988 were reviewed. The ventricular septal defect was subcristal in 50 and subpulmonary in 20 patients. Two thirds were situated immediately below some part of the right coronary leaflet with prolapse of that leaflet. Most of the remainder were below the right commissure or the anterior part of the noncoronary leaflet with prolapse of one or both adjacent leaflets. Associated structural defects, usually including some fusion at a commissure, were present in 18 of the 70 patients and occurred more often with a ventricular septal defect in or below the commissure between the right and noncoronary leaflets (p less than 0.001). Follow-up ranged from 1.9 to 19.6 (mean 9.8) years. There were no early deaths or cases of atrioventricular block, but there were two late deaths. Patient survival rate was 96% at 10 years. Freedom from valvuloplasty failure and freedom from reoperation were 76% and 85%, respectively, at 10 years. The major predictor for failure by multivariate analysis was the presence of an associated structural defect (p less than 0.01). Age at repair and position of the ventricular septal defect were not significant risk factors. We conclude that aortic valvuloplasty produces good palliation in most children. The few failures occurred early and chiefly in patients with associated structural valve defects that occurred more frequently in children who had a ventricular septal defect in the right commissure, where both the right and noncoronary leaflets may be affected.