Patent ductus arteriosus is an uncommon anomaly in adult patients. Surgical closure of patent ductus arteriosus in this age group presents difficult problems to the surgeon. We report our experience of 21 adult patients (19-62 years of age, mean 40 years) who underwent closure of the ductus by transfemoral implantation of a Rashkind double umbrella device. The patients came to light because of atrial fibrillation, congestive heart failure, residual flow after surgical ligation of the duct or because of incidental diagnosis made during physical examination or chest X-ray. In ten patients the pulmonary arterial pressure was normal (systolic pressure < 30 mmHg), in eleven it was elevated (systolic pressure from 30 to 100 mmHg, mean 50 mmHg). In seven patients the duct was clearly calcified and the size of the duct varied from 3 to 9 mm (mean 4.3 mm). In 16 patients the ductus resulted perfectly closed after implantation of the first double umbrella device, two patients had minimal residual aortopulmonary flow, whereas in three patients the residual shunt was significant; two of these also developed haemolysis and went to surgery, in the latter the shunt was completely abolished after implantation of a second 17-mm device 16 months later. In conclusion transcatheter closure of patent ductus arteriosus in adults is feasible, even in the presence of calcifications and/or pulmonary hypertension; taking into account the significant surgical risk, PDA umbrella closure should be considered the first choice procedure in this group of patients.