The surgical results of mitral valve plasty (MVP) for active infective endocarditis of the mitral valve was compared with that of mitral valve replacement (MVR).We operated on 30 successive patients with active infective endocarditis of the mitral valve. Eleven patients, including two cases with annular abscess, had MVP (MVP group), and 19 had MVR (MVR group). MVP was performed by resection of the infected part of the mitral valve, chordoplasty using artificial chordae, annuloplasty with or without a prosthetic ring.No operative nor hospital death was seen in MVP group. In MVR group, one operative death and one hospital death were noted. No patients in MVP group developed recurrence of the infection and one patient in MVR group developed prosthetic valve endocarditis. After MVP, no mitral regurgitation (MR) was found in six cases, slight MR in three cases, moderate MR in one case, and severe MR in one case. MVR was performed for the patient with severe MR.In conclusion, if the infective lesion of the mitral valve was resectable, the surgical results of mitral valve plasty for active infective endocarditis of the mitral valve was satisfactory.