Surgical treatment of neonates with pulmonary atresia and intact ventricular septum is associated with a high morbidity and mortality. During the last two years specific radiofrequency-catheters have been developed, which allow the interventional perforation and subsequent balloon dilatation of an atretic pulmonary valve during cardiac catheterization. We report our experience with this new interventional technique in two neonates. In the first case perforation and balloon dilatation of the atretic pulmonary valve was performed without a complication. In the second case the radiofrequency catheter perforated the right ventricular outflow tract. There was no pericardial tamponade and the patient underwent a surgical valvotomy the following day. In our experience radiofrequency-assisted balloon dilatation of the pulmonary valve is a possible alternative in the treatment of neonates with pulmonary atresia, intact ventricular septum and moderate hypoplasia of the right ventricle. Further experience will have to show, whether this new interventional technique can be generally recommended.