Objectives: We investigated the outcome of transcatheter closure using a single device in patients with multiple ASDs. Methods: From May 2003 to November 2008, 429 patients underwent transcatheter closure of ASD in our institute. Among them, 65 patients had multiple ASDs, and transcatheter closure was performed using a single device in all patients. We reviewed the outcome of the procedure, complications and serial echocardiographic findings. Results: The presence of multiple defects was diagnosed by echocardiography before the procedure in 50 patients (77%), and by transesophageal or intracardiac echocardiography at the time of procedure in 15 patients (23%). Largest defect size was 16.9±6.0mm (7mm-32mm), smallest defect size was 5.8±3.0mm (2mm-13mm) and total defect size was 23.0±7.6mm (10mm-37mm). Distance between the margins of the defects was ranged from 2mm to 19mm. The average balloon occlusive diameter and device size were 22.9±7.6mm and 23.1±7.7mm. Follow-up echocardiography performed after one day of the procedure revealed 51 patients (78.5%) with complete closure or trace residual shunt flow, 87.7% after 1month, 91.5% after 3month, 94.8% after 6month and 100% after 1year. All patients had no major complications. Conclusion: Transcatheter closure of ASD with a single ASO is an effective and feasible therapeutic option in patients with multiple defects. Distance between the defects and device size larger than total defect may have an important role in complete closure of the multiple ASDs with single device. Nevertheless, remaining defects, even in distant locations, can be closed spontaneously or further reduced in size after closure of the largest defect.