This study presents the initial experience of the pediatric Cardiology Unit, Cairo University in the treatment of congenital valvular aortic stenosis (AS) and coarctation of the aorta (CoA) with percutaneous balloon dilatation. Twenty-six patients were submitted to the procedure, 21 males and 5 females. They were divided into two groups; group I consisted of 14 cases (53%) with valvular AS having a mean age of 3.5 ± 2.6 years (ranging from 1.5 months to 7 years); group II included 12 cases (46%) with CoA, having a mean age of 3.4 ± 2.4 years (ranging from 6 months to 9 years). Four patients from group II had surgical recoarctation. Two cases were dysmorphic. Valvuloplasty was successful in 13 (92%) of 14 cases of group I with moderate to severe AS, with reduction of peak aortic valve gradient from a mean of 79 ± 17 to 31 12 mmHg (p<0.001). This was achieved by a single balloon and the mean balloon/annulus ratio was 0.9 ± 0.06. After balloon angioplasty done for 12 cases of group II, either with native CoA or surgical recoarctation, the peak-to-peak aortic pressure gradient decreased significantly from 38 ± 11 to 22 ± 11 mmHg (p < 0.001). The survival rate after balloon dilatation was excellent, with 96% survival at 18 months. Repeated echo-Doppler studies were performed 1 week to 18 months after initial dilatation, evaluating both systolic and diastolic functions of the left ventricle and comparing them with those obtained prior to the procedure. Peak instantaneous pressure gradients for both aortic stenosis and coarctation remained significantly lower compared with gradients before dilatation (40 ± 35 mmHg, 22 ± 3.5 mmHg respectively). At short-term follow-up, 3 (11%) of 26 cases had restenosis and underwent surgical resection for CoA (1 patient), repeat valvuloplasty for one case with AS and stent implantation was done for the third case with CoA. Temporary loss of femoral pulse was observed in 3 out of 26 cases (11%). Induced aortic insufficiency was mild to moderate in 21% of cases of group I, none requiring any surgical intervention. On follow-up, none of the patients from group II developed any aneurysms at the site of dilatation. We conclude that balloon dilatation is a successful technique in relieving congenital obstructive lesions of the heart in pediatric patients.