The surgical management of congenital aortic stenosis in 33 patients (age 2-20, mean 11 years) is described. The stenosis was valvular in 19 cases, subvalvular in eight and supravalvular in six. The primary procedures in valvular stenosis were valvotomy (12 cases), valve replacement (6) and exploration (1). Subvalvular stenosis was treated with resection of muscle (4), membrane (2) or both (2), and all six supravalvular lesions with patch aortoplasty. One death occurred during primary operation. Follow-up averaged 11.5 years. Of the 12 valvotomized patients, five required valve replacement after on average 10.6 years because of restenosis. Aortic regurgitation developed in six of the seven surviving patients treated for subvalvular stenosis, requiring reoperation in four. No mortality was associated with reoperation. All patients without valve replacement were reinvestigated. Of the seven with valvotomy, four had restenosis and three valves were in good condition. In supravalvular stenosis the gradients were low. Valvotomy and subvalvular resection can give effective palliation of aortic stenosis until the patient is old enough for definitive repair.