Aortic valvotomy (AV) for relief of congenital aortic stenosis (AS) is a palliative operation, and the purpose of this study was to determine the long-term benefit. After analyzing the symptoms at time of operation, 177 patients were separated by age at AV: newborns (1-14 days) 26, infants (2 weeks-1 year) 19, and children (≥1 year) 132. The newborn with critical AS typically presents with severe cardiac failure and the infant with moderate failure, whereas children may be asymptomatic. In the newborn group, final diagnosis has been made exclusively by noninvasive cardiac echogram since 1984. The presence of a hypoplastic left ventricle (HLV) and/or endocardial fibroelastosis (EFE) are the most important determinants of mortality. Operative survival was 11 of 13 (85%) in the newborn group if HLV/EFE were not present. No operative deaths for AV occurred after 1965 in children. When present, a preoperative electrocardiographic strain pattern resolved in 80% of patients. Of 33 reoperations (21%), four were required 1.0 (0.5-2) years later for newborns, five were required for infants 7.2 (1.5-20) years later, and 24 were required in children 11.0 (1.5-25) years later. These included 10 repeat valvotomies and 23 aortic valve replacements (AVRs) with a 91% survival rate. In summary, although valves of patients with congenital AS are morphologically abnormal, valvotomy is beneficial. It was found that (1) the operative survival rate has been 100% over the past 20 years for children and currently is greater than 80% in newborns in the absence of HLV/EFE; (2) reoperation rate is higher in newborns and infants; (3) benefit was shown by a sharp decrease in obstruction inititally and improved ECG later; (4) long-term follow-up revealed a subset of patients who are asymptomatic and have only mild residual obstruction over 20 years after AV.