Objective To investigate the optimal timing for surgical treatment of infants less than six months of age with tetralogy of Fallot (TOF), and to improve surgical results and reduce early mortality. Methods Clinical material of 108 consecutive patients with TOF who were less than six months of age undergoing early surgery from Oct.1996 to Dec. 2006 were retrospectively reviewed. There were 70 males and females with mean age of 4.70 months (9 d-6 months). 104 patients underwent complete repair and four patients underwent BlalockTaussig (B T) shunt. Emergency procedures have been performed in 5 patients. Results Five patients (4.63%) died of low cardiac output syndrome (3 patients), pulmonary infection and acute respiratory distress syndrome (1 patient), and acute necrotizing enteritis (1 patient).82 patients were followed up, followup period was 31.17±40.00 months.21 patients lost to followup. One patient(0.92%) required additional intervention for pulmonary valve stenosis 6 months after operation. Heart functional class(New York Heart Association) recovered toⅠ-Ⅱgrading in other patients. Echocardiography shows: no residual ventricular shunt, no stenosis in right ventricular outflow tract and pulmonary valve, pressure difference≤50 mm Hg. No late deaths. Conclusion Early definitive repair of TOF can be performed safely on infants less than six months of age, the results of low mortality is acceptable.