A 14-year-old patient with severe aortic coarctation was treated by advancing a balloon catheter across the stenosis via the right femoral artery. The 4 cm long balloon, transversal diameter 15 mm, was filled with saline containing contrast media for 10 seconds. The excess pressure in the balloon was 3.5 at. Subsequently the stenosis diameter increased from 3 to 7.3 mm. The systolic pressure gradient decreased from 75 to 35 mm Hg. After the operation the foot-pulse was palpable for the first time. The highly elevated arterial pressure in the upper extremities decreased markedly. Three months after the operation the vessel diameter was 10.2 mm and the pressure gradient only 10 mm Hg.