BACKGROUND: Pulmonary atresia and intact ventricular septum is characterised by a great morphological variety. Treatment is not uniform. OBJECTIVE: To evaluate our experience with transcatheter valvotomy and balloon dilatation in neonates with pulmonary atresia and intact ventricular septum. DESIGN: Retrospective. METHODS: Between January 1997 and September 2000 five neonates with pulmonary atresia and intact ventricular septum underwent transcatheter valvotomy and balloon dilatation. RESULTS: The catheter intervention was performed at a mean age of 27 days (range 3-95 days). The atretic pulmonary valve was successfully perforated in all neonates. Subsequent balloon dilatation was successful in four neonates. Balloon dilatation was unsuccessful in one patient, who underwent an elective surgical valvotomy of the pulmonary valve after five days. Three patients needed a modified Blalock-Taussig shunt after a mean of 23 days. Four patients required repeated balloon dilatation after a mean of 227 days. Mean follow-up was 2.7 years (range 1-5 years). CONCLUSIONS: Transcatheter perforation of the pulmonary valve membrane and balloon dilatation is a good, safe initial therapy in selected neonates with pulmonary atresia and intact ventricular septum. This procedure can prevent open-heart surgery in these patients in the first months of life