The current study compared clinical outcomes after mitral valve repair or replacement in patients with active infective endocarditis involving only the native mitral valve. From January 1994 to December 2009, 102 patients were identified with active infective native mitral valve endocarditis. Mitral valve repair (MVP) was performed in 41 patients and mitral valve replacement (MVR) in 61 patients. The mean age was 34.4 ± 16.9 years in the MVP group and 43.1 ± 14.9 years in the MVR group (p=0.007). The composite end points of cardiac death and cardiac-related morbidities were compared in these two groups using the inverse-probability-of-treatment-weighted method. The median follow-up time was 4.7 years (range, 0.1-15.8) and follow-up was possible in 100 (98%) patients. There were three in-hospital deaths (2.9%), all in MVR patients (p=0.272). The mean cardiopulmonary bypass time and aortic cross-clamping time were 111.4 ± 34.7 min and 72.7 ± 23.7 min in the MVP group and 101.1 ± 42.9 min and 62.9 ± 26.9 min in the MVR group (p=0.204, p=0.062). The 1-, 5-, and 10-year survival rates were 97.5%, 97.5%, and 81.1%, respectively, in the MVP group and 90%, 85.8%, and 85.8%, respectively, in the MVR group (p=0.316). Actuarial event-free survival at 1, 5, and 10 years was 92.7%, 89.5%, and 72.2% in the MVP group, and 94.8%, 81.0%, and 77.3% in the MVR group (p=0.787), respectively. The present study showed that postoperative long-term survival and event-free survival in patients with active infective endocarditis of the native mitral valve were not statistically significantly different regardless of whether patients underwent MVP or MVR.