OBJECTIVE The purpose of this study was to evaluate the outcome after one-stage repair of TOF. METHODS Between May 1997 and December 2002, 240 patients with a median age of 9 months (range, 16 days to 48 years) underwent one-stage repair of TOF. Among these, 46 patients (19.2%) were under 6 months of age. Closure of VSD was accomplished through right atrium in 171 patients (71.3%) and through right ventricle in 69 patients (28.7%). For the reconstruction of right ventricular outflow tract, transannular repair was performed in 151 patients (62.9%), and non-transannular repair was performed in 89 patients (37.1%). Follow-up was complete, averaging 40.0짹17.6 months (range, 3 months to 5.8 years). RESULTS There were two operative deaths (0.8%) and one late death. Five patients required late reoperations due to right ventricular outflow tract obstruction (n=3), and residual VSD (n=2). 9 patients underwent balloon pulmonary angioplasty for peripheral pulmonary artery stenosis. Kaplan-Meier freedom from reoperation at 5 years was 98.3짹1.0%. Between early repair group (age under 6 months) and late repair group, there were no difference in the route for VSD closure and the method of right ventricular outflow tract reconstruction. Ventilator time, duration of inotropic support, and ICU stay were longer in the early repair group (p<0.05). All survivors are currently in NYHA class I. CONCLUSIONS One-stage repair of TOF could be performed with low mortality & morbidity. Especially, early one-stage repair in symptomatic infant could be performed with low risk, eliminating the need for palliative procedures.