A 68-year-old woman was admitted with congestive heart failure and septic shock associated with suspected mitral valve acute infective endocarditis. Echocardiography revealed vegetations attached to both mitral leaflets, prolapse of the posterior mitral leaflet and severe mitral regurgitation. Emergent surgery was performed. The anterior mitral leaflet displayed multiple vegetations. The entire anterior leaflet of mitral valve was replaced with pericardium. The posterior mitral leaflet of the middle scallop was prolapsed with an attached vegetation. Quadrangular resection was performed. A commissural reconstruction by sliding commissuroplasty for a prolapse of both anterior and posterior leaflets in the paracommissural area and autologous pericardial mitral annuloplasty was performed. Mitral regurgitation disappeared postoperatively, and the patient is now doing well as of 5 years postoperatively.