Objectives: Debate on the proper timing of pulmonary valve replacement (PVR) after repair of tetralogy of Fallot (TOF) is still continuing. Significant pulmonary regurgitation (PR) could result in right ventricular (RV) dysfunction, exercise intolerance, arrhythmia, and sudden death. We analyzed clinical results of PVR after repair of TOF to investigate potential risk factor for late outcomes. Methods: From January 1993 to July 2002, 58 patients (38 males and 20 females) received PVR after repair of TOF. More than moderate degree of PR was observed in these patients by echocardiography. Mean age at PVR was 13.5±9.6 years (1.2–44) and TOF repair was performed at 5.2±7.1 years of age (0.5–34). Therefore, PVR was performed at 8.3±5.2 years (4 months–28 years) after repair. Preoperative electrocardiogram showed complete right bundle branch block in 49 patients (84.5%). Mean duration of QRS complex was 142±30 ms. Major arrhythmia occurred in eight patients. Twenty-nine patients complained decreased physical activity and 10 patients showed clinical signs of right heart failure. Results: Early death occurred in one patient (2.5%). Major complication occurred in three patients (complete heart block in two, aortic rupture in one). Follow-up was performed for 2.5±2.4 years (46 days–10.3 years). There was no late death. Postoperative cardiothoracic ratio was significantly decreased (0.61±0.07 to 0.55±0.06, P<0.001). Marked symptomatic improvement was noted in all patients. Postoperative symptomatic group (n=14) showed older age at repair of TOF (12.5±10.7 vs 2.6±2.3 years, P=0.003), older age at PVR (23.2±12.8 vs 10.1±5.0 years, P=0.001), longer interval between repair of TOF and PVR (10.6±7.0 vs 7.5±4.2 years, P<0.05), higher degree of functional class (2.4±0.5 vs 1.4±0.8, P<0.001), and longer duration of hospitalization (30.0±14.2 vs 18.9±11.4 days, P=0.004) than postoperative asymptomatic group (n=43). Conclusions: In patients with significant PR after repair of TOF, PVR had clinical benefits including symptomatic improvement with low mortality and morbidity. Proper timing must be carefully selected according to objective evaluation of RV function. In our study, earlier PVR prior to symptomatic manifestation showed beneficial effects.