Objectives: To compare surgical as opposed to percutaneous interventional closure of isolated atrial septal defects in the oval fossa in terms of hospital stay, efficacy, and complications, and to study the respective role of the two techniques in current practice. Methods: Between January 1998 and April 2004, 126 out of 1210 patients treated at our institution for closure of an isolated defect in the oval fossa were aged less than 6 years. The mean age of these 126 patients at procedure was 4.2 plus or minus 1 year. The ratio of females to males was 74 to 52. Results: Of the patients, 62% were treated successfully using a percutaneous approach. The groups treated surgically or percutaneously did not differ for age, gender, or indications for treatment. No deaths occurred. The rates of total and major complications were higher in the group undergoing surgical closure, at 34% versus 9%, p less than 0.0001, and 10.5% versus 1%, p equal to 0.01, respectively. Embolisation of the device requiring subsequent surgery occurred in 1% of patients. The stay in hospital was shorter in those closed percutaneously, at 3.2 plus or minus 0.9 days versus 6.8 plus or minus 2.8 days, p equal to 0.0001. During a mean follow-up of 3.4 plus or minus 1.9 years, no major complications occurred in either group, and symptoms improved significantly in both groups. Additional sequels occurred in 2 patients who had major complications subsequent to surgical closure. Conclusions: Even in young children, it is both feasible and safe to close defects in the oval fossa percutaneously. Compared to surgical closure, the transcatheter approach allows a shorter stay in hospital, and has a lower rate of complications. Early and mid-term follow-up has confirmed the safety and efficacy of both techniques.