Objectives: To determine the long-term outcomes and risk factors for, reintervention after balloon dilation of congenital aortic stenosis in children aged 6 months or older. Background: Although balloon dilation of congenital aortic stenosis has become a primary therapeutic strategy, few data are available regarding long-term outcomes. Methods: We carried out a retrospective review of 87 children who had undergone balloon dilation of the aortic valve at median age of 6.9 years. Results: The procedure was completed in 98% of the children, with an average reduction in the gradient across the valve of 64 ± 28%, and without mortality. Of the children, 76 had been followed for a mean of 6.3 ± 4.2 years. Reintervention on the aortic valve was required in 32 children, with 12 undergoing reintervention within 6 months, with 1 death. Another patient had died over the period of follow-up due to a non-cardiac event. Estimated freedom from reintervention was 86% at 1 year, 67% at 5 years, and 46% at 12 years. Parametric modeling of the hazard function showed a brief early phase of increased risk, superimposed on an ongoing constant risk. The only incremental risk factor for the early phase was a residual gradient immediately subsequent to the procedure greater than 30 mmHg. Incremental risk factors for the constant phase included the presence of symmetric valvar opening, and greater than moderate regurgitation immediately after dilation. Conclusion: Long-term survival was excellent, albeit that the need for further reintervention was high due to the palliative nature of the procedure.