OBJECTIVE the aim of this study was to evaluate the long-term results of transcatheter balloon aortic valvuloplasty, the preferred treatment for congenital aortic stenosis (AS). BACKGROUND aortic valve function and reintervention late after this procedure are not well characterized. METHODS from 1985 to 2008, 563 patients underwent balloon dilation for congenital AS. After excluding those converted to univentricular circulation and/or died ≤ 30 days after the procedure, 509 patients constituted the study cohort. RESULTS The median follow-up period was 9.3 years (range 0.1 to 23.6 years); cumulative follow-up was 5,003 patient-years. The median age was 2.4 years (range 1 day to 40.5 years), and most patients (73%) had isolated native AS. Peak AS gradients decreased significantly after dilation (median decrease, 35 mm Hg), and acute post-dilation aortic regurgitation was moderate or greater in 70 patients (14%). Older patients more often had post-dilation aortic regurgitation (p < 0.001). During follow-up, 225 patients (44%) underwent aortic valve reintervention: repeat balloon dilation in 115 (23%), aortic valve repair in 65 (13%), and aortic valve replacement in 116 (23%). Survival free from any aortic valve reintervention was 89 ± 1% at 1 year, 72 ± 2% at 5 years, 54 ± 3% at 10 years, and 27 ± 3% at 20 years. Freedom from aortic valve replacement was 90 ± 2% at 5 years, 79 ± 3% at 10 years, and 53 ± 4% at 20 years. In multivariate analyses, lower post-dilation AS gradient and lower grade of post-dilation aortic regurgitation were associated with longer freedom from aortic valve replacement, but age, era, and pre-dilation AS severity were not. CONCLUSIONS although transcatheter aortic valvuloplasty is effective for relief of congenital AS, there are steady long-term hazards for surgical aortic valve reintervention and replacement that are independent of age at initial intervention or AS severity.