Balloon dilatation of congenital stenotic lesions of the heart and great vessels has been used for more than a decade. Varying incidence of residual obstruction or recurrence, hereafter referred to as restenosis, has been observed at follow-up. The purpose of this study was to evaluate the feasibility and effectiveness of repeated balloon dilatation of restenosed lesions after previous balloon dilatation for pulmonic (PS) and aortic (AS) stenosis and native aortic coarctation (AC). Neonates, infants, and children (n = 178) underwent balloon valvoplasty/angioplasty with reduction (p < 0.001) or peak-to-peak systolic pressure gradients from 91 +/- 41 (mean +/- SD) mm Hg to 25 +/- 19 mm Hg, from 70 +/- 20 mm Hg to 26 +/- 12 mm Hg, and from 48 +/- 17 mm Hg, to 11 +/- 9 mm Hg in patients with PS, AS, and AC, respectively. Repeated catheterization or echo-Doppler studies or both were performed from 3 months to 5 years after initial balloon dilatation. Residual gradients at follow-up were 26 +/- 26 mm Hg, 34 +/- 20 mm Hg, and 16 +/- 15 mm Hg, respectively, for PS, AS, and AC and remained significantly lower (p < 0.01) compared with gradients before the balloon dilatation. However, when results of individual patients were scrutinized, 9 (11%) of 80 patients with PS, 6 (23%) of 26 patients with AS, and 16 (27%) of 60 patients with AC had restenosis, on the basis of standard criteria. Repeated balloon dilatation was performed with reduction (p < 0.05 to < 0.001) of peak-to-peak gradients from 89 +/- 40 mm Hg to 38 +/- 20 mm Hg in 9 patients with PS, from 77 mm Hg to 13 mm Hg and 66 mm Hg to 6 mm Hg, respectively, in 2 patients with AS, and from 38 +/- 11 mm Hg to 10 +/- 6 mm Hg in 12 patients with AC. Echo-Doppler studies, 2 to 6.5 years after repeated balloon dilatation, indicated excellent results, with residual peak instantaneous Doppler gradients of 24 +/- 13 mm Hg in PS, 43 +/- 20 mm Hg in AS, and 11 +/- 6 mm Hg in AC groups, respectively. This improvement is irrespective of the cause of restenosis after initial balloon valvuloplasty/angioplasty. From this experience, we conclude that repeated balloon dilatation is feasible and effective in relieving restenosis after initial balloon valvuloplasty/angioplasty.