Seventy-six patients, with a mean age of 11.6 years, presenting with congenital subvalvar aortic stenosis were operated upon between 1965 and 1979. Seventy had moderate subvalvular stenosis. Eighty-eight percent had myotomy combined with resection of the obstruction. Five patients (6.6%) died postoperatively. Of 48 survivors followed up between 6 months to 13 years postoperatively (mean 4.2 years), 4 underwent reoperation and 2 of them died. Survival at 5 years and 10 years was 96% and survival without reoperation at 5 years and 10 years was 91%. When last seen, 90% of the patients were asymptomatic, left ventricular hypertrophy on ECG had disappeared in 63%. No patient had atrioventricular block. Two thirds of the patients had no systolic thrill and of 13 patients recatheterized (3.2 years follow-up) 9 had a peak systolic gradient below 50 mmHg. If, postoperatively 60% of the patients had aortic insufficiency versus 31% preoperatively for the whole period, this percentage fell to 33% after 1976. As subaortic stenosis is a progressive disease and late surgical results are correlated to preoperative peak systolic gradient, early surgery is recommended. Close postoperative follow-up is needed since recurrence of aortic stenosis is possible (and acquired aortic insufficiency may persist).