Aims. Long-term follow-up of patients with aortic valve stenosis undergoing balloon valvuloplasty was evaluated with respect to survival, the need for repeat intervention and factors predicting late outcome. Methods and Results. Forty-five patients between 3.5 to 23 years old (mean 11.7 +/- 4.5) were followed for 62 +/- 30 months (range 11-122). The transvalvar aortic gradient decreased from 84 +/- 20 to 36 +/- 10 mmHg (p < 0.001) and remained significantly lower (50 +/- 26 mmHg; p < 0.001) at follow-up. At that time, 10 patients (including 4 with significant valve incompetence) had gradients greater than or equal to 60 mmHg. The procedure resulted in significant valve incompetence (grade greater than or equal to 3) in 8 patients (17.8%). There was a progression of incompetence and 13 patients (28.9%) had significant regurgitation at follow-up. All survived. Fifteen patients (33.3%) required re-intervention 51 +/- 24 months after valvuloplasty. The indications mere: aortic stenosis in 5 patients; regurgitation in 6 patients; and stenosis with regurgitation in 4 patients. Actuarial freedom from re-intervention at 2, 4, 6 and 8 years was 96%, 88%, 61% and 56% of patients, respectively. The residual post-valvuloplasty gradient was the only predictor of re-intervention for valve stenosis (odds ratio = 3.2 for every 10 mmHg gradient increase; p = 0.017). A residual post-valvuloplasty gradient greater than or equal to 40 mmHg increased the relative risk of reintervention sixfold. The immediate post-valvuloplasty aortic regurgitation grade was the only risk factor of re-intervention for regurgitation (odds ratio = 34 for every incompetence degree increase; p = 0.0019). Incompetence grade greater than or equal to 2 increased the risk of reintervention tenfold. Conclusions. Valvuloplasty carries the risk of development of valve incompetence, which progresses with time. Some patients develop restenosis. The 6 10 year survival after the procedure is excellent, and 56% of patients are free of re-intervention at 8 years. The immediate post-valvuloplasty incompetence grade and transvalvar gradient are the predictors of late re-intervention.