PURPOSE: Transcatheter closure of the patent ductus arteriosus (PDA) is a well established alternative to surgical treatment. The aim of this study was to analyze safety, efficacy and follow up results of percutaneous closure of a moderate-to-large sized PDA. METHODS: Between November 1999 and October 2004, eighty-two patients underwent attempted transcatheter closure of a moderate to-large sized PDA. Age at intervention ranged from 9 months to 68 years (18.4+/-18.3 years). Body weight ranged from 7.8 kg to 74 kg (34.0+/-21.3 kg). RESULTS: The mean PDA diameter was 4.5+/-1.3 mm. The type of PDA was conical (72 patients), tubular (9 patients), other (1 patient, dumbbell shape). The devices used were Amplatzer Ductal Occluder (ADO(R), 64 cases), Detachable Coil (14 cases), and Duct Occlud (3 cases). Total complete closure rate was 93%. Complete closure was achieved in 58 patients (78%) at the end of procedure, 8 patients (11%) at 1week, 4 patients (5%) at 1 month, and 4 patients (5%) at 1 year, respectively. A residual shunt was present in three patients (4%). Complications occurred in eight patients: stenosis of left pulmonary artery (4 patients), hemolytic anemia (2 patients), infective endocarditis (1 patient), and device embolization (1 patient). CONCLUSION: Transcatheter closure of a moderate to-large sized PDA using the device is a safe and effective treatment with a favorable short and mid-term results. For optimal results, appropriate devices should be selected in relevance to PDA morphology and diameter, age, body weight, and +++economical factor.