Background: There is limited published outcome data on the STARFlex® device for transcatheter closure of atrial septal defects (ASD). Aim: To contribute to the long term outcomes of ASD device closure with the STARFlex® device. Methods: Results of a prospective FDA approved clinical trial (1999-2001) from a single institution of the STARFlex device for simple ASD was reviewed. The inclusion criteria included age ≥2 years, isolated secundum ASD, evidence of right ventricular volume overload, and maximum stretched diameter <22 mm. A retrospective review of the original study data with most recent follow-up was performed. Clinical success in the trial was defined as complete closure or residual leak ≤2 mm, absence of a severe complication and no need for an additional device or surgery to treat the ASD. Results: Twenty seven (27) patients were prospectively enrolled in the study period with a procedural success in 23 (85%). There were two severe complications, both 40 mm device embolizations that underwent semiurgent surgical intervention for device removal and ASD closure (40 mm device subsequently withdrawn from trial). Device placement was unsuccessful in two patients due to malposition related to an insufficient retro-aortic rim, with elective surgical closure. Unsuccessful procedural outcomes were statistically associated with deficient rims (P < 0.01). Of the 23 long term follow-up device patients, 23 (100%) achieved clinical success: 22 (96%) had complete closure at 1 year and latest echocardiographic follow-up and one case had a small <2 mm residual defect that has persisted. There have been no late complications with normalization of RV volumes in 92% and no deleterious ECG changes. Device fractures occurred in 8/23 (35%) devices and were more common in the larger devices (P < 0.05) but had no sequalae. None required any further intervention to treat the ASD and there were no infectious or thrombotic issues. Conclusions: In this cohort the STARFlex device for secundum ASD closure provided procedural success in 85% with failures due to surgical referral. All 23 patients with a STARFlex device with available long term follow-up had clinical success. Further long term data is required. © 2009 Wiley-Liss, Inc.