Aim: We sought to investigate the safety and efficacy of Cardio-O-Fix septal occluder (CSO) in percutaneous closure of atrial septal defects (ASD) as compared to the Amplatzer septal occluder (ASO). Methods: A consecutive of 351 patients received transcatheter ASD closure with CSO or ASO from July 2004 to October 2010 were studied. The ASDs were divided into simple- (isolated defects <26 mm) or complex-types (isolated defect ≥26 mm, double or multifenestrated defects). The procedures were guided by fluoroscopy and transthoracic or transesophageal echocardiography. Clinical and echocardiographic follow-ups were arranged before discharge, at 1 month and then every 6-month after implantation. Results: During the study period, 185 (125 males, aged 18.5 ± 15.6 years) and 166 (103 males, aged 21.0 ± 15.7 years) patients attempted CSO and ASO implants, respectively. The CSO group had similar ASD and device sizes, prevalence of complex lesions (17 vs. 16%, P = 0.796), procedural times and success rates (97% vs. 96%, P = 0.635) as compared to the ASO group. Acute residual shunts were less prevalent in CSO than ASO group and most shunts closed spontaneously at 6-month follow-ups. The average equipment cost per patient was lower in CSO group (US$ 4,100 vs. US$ 5,900, P < 0.001). The prevalence of device embolization and atrial arrhythmia (all <2%) were similar in both patient groups. Conclusion: Transcatheter ASD occlusion with CSO is safe and effective and it appeared to be an attractive alternative to ASO in closing simple-type ASD because of its relatively low cost. © 2013 Wiley Periodicals, Inc.