Mitral valve repair is preferred to replacement in infective endocarditis, but in the active phase, it often requires extensive debridement of infected tissue and complex reconstruction. We investigated 22 consecutive native mitral valve operations during active-phase infective endocarditis. The time from initiation of medical treatment to operation was 16.8 ± 16.4 days. Mitral valve repair was performed in 15 (68.2%) patients, using prosthetic annuloplasty in 14, an autologous pericardial patch in 11, and artificial chordal replacement in 9. Hospital mortality was 9.1% (2 patients), due to subarachnoid hemorrhage and pneumonia. One patient died 26 months after valve replacement due to congestive heart failure. The postoperative left ventricular end-diastolic dimension was significantly smaller (45.7 ± 5.6 vs. 53.3 ± 10.2 mm) and ejection fraction was significantly higher (57.0% ± 14.7% vs. 40.1% ± 8.2%) in patients who underwent valve repair compared to those who had valve replacement. Mitral regurgitation requiring reoperation occurred in 3 patients during follow-up. Mitral valve repair is feasible in active-phase infective endocarditis, and results in improved regression of left ventricular dimensions compared to valve replacement. However, complex mitral valve repair with extensive leaflet resection may not have long-term durability.