A 17 month old girl with tricuspid atresia, ventricular septal defect, subvalvar and valvar pulmonary stenosis, and increasing cyanosis had angiographic evidence of proximal stenosis of a right modified (5 mm diameter) Blalock-Taussig shunt. She underwent palliative balloon angioplasty with a 6 mm Schneider balloon catheter. Successful dilatation was achieved without complication. Four months later there was subjective clinical improvement with a rise in systemic arterial saturation. Repeat angiography showed patency of the shunt without restenosis or formation of an aneurysm.