Background: Fontan revision has been demonstrated to provide hemodynamic and symptomatic improvement in select patients with failing Fontan circulations. This study was designed to assess intermediate results of Fontan conversion (FC) for salvaging the failing Fontan. Methods: From January 1996 to June 2006, 23 patients underwent Fontan revision in the SNUCH. A retrospective analysis of these patients' charts was performed. Results: Mean age at initial Fontan operations was 4.87짹 3.29 (range: 1.1-15.5) years and mean age at FC was 17.03 짹 6.19 (range: 5.5-30.5). The 1st Fontan operations were atriopulmonary connections in 19 patients, extracardiac lateral tunnel (LT) in 1, intracardiac LT in 2, and extracardiac conduit (ECC) in 1. FC operation was performed with intracardiac LT in 5 patients and ECC in 18. Seventeen patients developed atrial flutter and 14 patients out of them had medically uncontrolled atrial flutter. Sinus node dysfunction was observed in 13 patients. Arrhythmia surgery included isthmus cryoablation in 13 patients and right-sided maze in 5. Mean follow-up duration was 3.36짹 2.88 (range: 0.1-9.7) years. Fourteen patients was required permanent pacemaker. Almost patients excepts 3 patients have improved to New York Heart Association class I or II. There was two operative mortality (8.7%). All of them had preoperatively protein-losing enteropathy. During follow-up, 8 patients recurred tachycardia, including atrial flutter and junctional tachycardia, and 7 patients' tachycardias were medically well-controlled. Seventeen patients has had reasonable ventricular function by echocardiography. Conclusions: This study indicates that Fontan conversion is associated with an improvement of single ventricular function, heart failure symptoms and refractory arrhythmias. However, the results of the Fontan conversion in patients with protein losing-enteropathy were unsatisfactory.