Abstract Background Aortic stenosis (AS) is encountered in approximately 5% of children with heart disease. The indications for surgery and the surgical techniques for AS are well established. This report focuses on the early and long-term outcomes in children with AS over a 40-year period. Methods Included in this study were 508 patients ranging in ages from 1 day to 19 years, who were operated on for AS between 1960 and 2002 . Eighty-one percent (414 of 508) of the patients had left ventricular outflow tract obstruction (LVOTO) at a single level: 40 supravalvar, 242 valvar (critical AS in 85 neonates and young infants and in 157 older children), and 132 subvalvar. Nineteen percent (94 of 508) of the patients had LVOTO at more than one level. Associated congenital cardiac defects were found in 32% of the patients. Results The overall hospital mortality rate was 8% (40/508) with neonates with critical AS having the highest mortality (33%). The late mortality was 4% for the entire group. Follow-up was 95% complete. The mean follow-up was 8.5 ± 7.1 years. In the subgroup with multilevel LVOTO (n = 94), the average intraoperative peak systolic left ventricular-aortic gradient decreased from 80 to 22 mm Hg after repair but increased progressively to 74 ± 36 mm Hg ( p < 0.05) before reintervention was required. One hundred twenty-one patients (24%) underwent 151 reoperations for recurrent or residual LVOTO or aortic regurgitation. Actuarial curves predict a 20-year survival of 88% and 62% freedom from reoperation for all patients with AS. Symptomatic improvement in survivors was excellent (90% New York Heart Association class I). Conclusions Surgical relief of LVOTO in infants and children can be accomplished with low mortality and morbidity. Neonates with critical AS have significantly higher mortality and morbidity due to their complex anatomy and their critical presentation that affects outcome. Aortic valvotomy delays valve replacement in a significant percentage of children. The Ross procedure and mechanical aortic valve replacements have had a low mortality and morbidity in our series. Valve replacement will eventually be required in most children presenting with valvar AS and multilevel LVOTO while repair of discrete subaortic stenosis and supravalvar AS may not require reoperation in most patients. Children with LVOTO should have lifetime follow-up.