Objectives: To evaluate feasibility, efficacy, and safety of an approach to atrial septal defect (ASD) occlusion in children ≤20 kg that eliminates cardiac wall erosion risk. Background: Cardiac wall erosion is a potentially catastrophic complication of ASD device closure. The HELEX Septal Occluder (HSO) is a compliant device with no reports of erosion. The HSO is technically difficult to deploy in smaller children and cannot be used to close larger defects. To eliminate wall erosion risk, we use the HSO when feasible and surgery for larger defects. Methods: Retrospective review of ASD procedures performed in children ≤20 kg. Results: Between January 2006 and January 2011, 60 children underwent ASD closure. HSO placement was successful in 32 of 34 patients, and surgical closure was successful in all of 28 patients. Surgical patients were younger (35.1 ± 12.6 vs. 47.4 ± 15.3 months, P < 0.01) and smaller (15.3 ± 3.2 vs. 12.6 ± 4.3 kg; P < 0.01) with larger ASDs (15.8 ± 4.5 vs. 9.8 ± 3.0 mm; P < 0.01). No surgical patients demonstrated residual leak. Residual leak was seen in 14 of 32 (44%) HSO patients on postprocedure day #1 and in 1 of 26 (3.8%) with ≥6 months follow-up. Indications for surgery included: deficient inferior/superior rims (n = 17), provider preference (n = 2), and HSO device not feasible (n = 9). Serious adverse events included device embolization with percutaneous retrieval (n = 1) and postpericardiotomy syndrome without intervention (n = 1). Conclusions: The HSO can be safely used in most children ≤20 kg. Our approach to ASD closure is associated with minimal morbidity and good short-term results. This approach requires no more than a 15% increase in surgical referrals and eliminates risk of cardiac wall erosion. © 2012 Wiley Periodicals, Inc.