A patent ductus arteriosus should be closed because of its hemodynamic significance and/or the risk of infective endocarditis. Mortality of surgery is low. In adults, however, technical problems can arise due to calcification of the ductus walls. Using the transfemoral plug technique, developed by Porstmann, we attempted a ductus closure without surgery on 35 patients. The youngest was an 11-year-old girl, the oldest a 63-year-old woman (mean age of all patients: 37 years). The pressure in the pulmonary artery ranged from 15/5 to 70/27 mmHg, the diameter of the ductus from 2 to 9 mm (mean: 4.4 mm). According to the size and shape of the ductus, a plug of polyvinyl alcohol (Ivalon) with an inner steel wire frame was prepared. Threaded over a long arterio-transductal venous track wire, the plug was introduced into the femoral artery and advanced into the ductus by a pushing catheter. After removal of the track wire the plug remained wedged in the ductus. In all 35 patients, transfemoral ductus closure was possible. Patients with complaints improved remarkably within some days. Heart size and pulmonary congestion decreased considerably. All patients were followed for a period of 1-46 months. In two of them, the ivalon plug embolized into a side branch of the left pulmonary artery 7 and 2 weeks after the procedure, but without serious consequences.(ABSTRACT TRUNCATED AT 250 WORDS)