Objectives: Describe the short and midterm outcome and to determine the predictors of reintervention in neonates with critical pulmonary stenosis (PS) or pulmonary atresia with intact ventricular septum (PA/IVS). Background: The transcatheter intervention for critical PS and PA/IVS resulted in improvement in the patient's survival and the quality of life. The procedure is not free of complications and there is still a significant rate of reintervention. Method: All neonates with critical PS or PA/IVS who underwent interventional cardiac catheterization between November 2004 and January 2009 were reviewed retrospectively. We performed a comparison between those who required reintervention and those who did not, to identify the predictors of reintervention. Results: Forty-three neonates were included, 23 (53.5%) had critical PS and 20 (46.5%) had PA/IVS. Twenty-six patients (60%) were males, the mean age was 11 ± 8 days, and the mean weight was 3.2 ± 0.6 kg. Two patients died (4.6%). The mean follow-up period was 19 ± 13 months for 42 patients. Fifteen patients (36%) required reintervention, 11 of them (73%) had PA/IVS, and 4 (27%) had critical PS. Reintervention was more in patients with PA/IVS than those with critical PS (P = 0.003). Other predictors for reintervention included hospital stay ≥ 7.5 days (P = 0.001) and tricuspid valve regurgitation peak gradient in day one post first intervention (TR1) ≥ 43 mm Hg (P = 0.03). Conclusion: Interventional cardiac catheterization shows favorable outcome for patients with critical PS and PA/IVS. Predictors for reintervention included the diagnosis of PA/IVS, hospital stay ≥7.5 days after first intervention and TR1 gradient ≥ 43 mm Hg. © 2011 Wiley Periodicals, Inc.