Objective: Although pulmonary valve replacement (PVR) is effective in reducing right ventricular (RV) volume overload in patients with chronic pulmonary regurgitation (PR) after relief of right ventricular outflow tract obstruction, the optimal timing of PVR is not well defined. The objectives of this study were to evaluate outcomes of PVR in patients with chronic PR and to better define the optimal timing of PVR. Methods: One hundred eighty-one patients who underwent PVR between January 1998 and March 2011 for chronic PR were retrospectively analyzed. To define the optimal timing of PVR, preoperative and postoperative cardiovascular magnetic resonance (CMR) data (n = 68) were analyzed. Results: The median age at the time of PVR was 16.7 years (4.5 - 60.2 years). Follow-up completeness was 93.8% and the median follow-up duration was 5.9 years (0.3 - 13.5 years). Overall and event-free survival at 10 years was 97.6 짹 1.5% and 71.8 짹 9.6%, respectively. There was a significant decrease in QRS duration (n = 81, 145 짹 29 ms versus 140 짹 26 ms, P = 0.001) and significant improvement in NYHA class (n = 156, 1.7 짹 0.6 versus 1.1 짹 0.3, P <0.001). Postoperative CMR showed significant reduction in RV volumes and significant improvement in biventricular function (Table). Receiver operating characteristic curve analysis revealed a cutoff value of 168 mL/m² for non-normalization of RV end-diastolic volume index (RV EDVI) and 79 mL/m² for RV end-systolic volume index (RV ESVI). Optimal outcome in terms of CMR parameters (normalized RV EDVI, RV ESVI, and RV EF) was achieved in 52% of the patients. Cutoff values for optimal outcome were 163 mL/m² for RV EDVI and 79 mL/m² for RV ESVI. Conclusions: Mid-term outcomes of PVR in patients with chronic PR were acceptable. Optimal outcome could not be achieved when preoperative RV EDVI >163 mL/m² or RV ESVI was >79 mL/m².