Between September 1980 and August 1988, 21 patients, of mean age 7.3 (range 1-19) years, with ventricular septal defect and aortic valve prolapse, underwent surgery. Aortic insufficiency was mild in three patients, moderate in 13 and severe in five. Surgical repair was performed using a combined transaortic and transpulmonary approach. The prolapsed leaflets were evaluated through the ventricular septal defect before and after valvuloplasty. Using the Trusler technique, the prolapsed cusps were plicated at the level of the commissures; only one patient required aortic valve replacement. After functional assessment of the valve repair, through the ventricular septal defect, during infusion of cardioplegia in the aortic root, the defects were closed through the pulmonary artery, or through a right atriotomy. Mean follow-up was 51.5 (range 3-108) months. One patient developed bacterial endocarditis and died 3 months after surgery. The other 20 patients remained symptom-free. There are no residual ventricular septal defects, and mild residual aortic insufficiency is present in six patients. The mean(s.d.) cardiothoracic ratio decreased from 0.61(0.07) before to 0.49(0.05) after surgery. In summary, preservation and repair of the prolapsed aortic valve is possible even in the presence of severe aortic insufficiency. The combined approach through both great arteries enables good visualization with minimal traction, and accurate assessment of the aortic valvuloplasty through the ventricular septal defect. In addition, problems associated with a right ventriculotomy are avoided.