Fifty-one patients, aged 1 to 18 years, having aortic valvotomy for congenital valvar aortic stenosis between 1956 and 1986 were followed up. The average age at operation was 11.5 years, with an operative mortality of 3.9%. The aortic valve gradient decreased from a mean preoperative value of 91 mm Hg to 27 mm Hg postoperatively. Current follow-up was 90% and averaged 16.8 years. Late cardiac mortality was 17.6%, with actuarial survival of 93.7% at 10 and 15 years, 81.8% at 20 and 25 years, and 70.9% at 28 years. Nineteen patients required reoperation (39%) at a mean of 17.7 years postoperatively, with a reoperation-free survival of 98% at 10 years. The reoperation rate accelerated in the following decade to 3.3% per year. Ten patients without reoperation were evaluated by continuous-wave Doppler echocardiography. The mean gradient was 21.6 mm Hg, and 90% had mild to moderate aortic insufficiency. This study confirms the efficacy of valvotomy in this age group and suggests that long-term survival and time to reoperation may be longer than previously reported.