An operative technique for mitral valve replacement (MVR) with preservation of the chordae tendineae to the anterior leaflet as well as the posterior leaflet is reported. This technique consists of the division of the anterior leaflet into anterior and posterior segments, the shifting and reattachment of the divided segments to the mitral ring of the respective commissural areas, and the use of a low-profile bileaflet prosthetic valve. A comparison of left ventricular function data between patients having operation with this technique and those having operation with the conventional method of MVR revealed significantly better improvement in cardiac index (p less than 0.06), left ventricular end-systolic volume index (p less than 0.05), and left ventricular ejection fraction (p less than 0.10) in the former group. Left ventricular wall motion improved in the anterolateral (p less than 0.01) and apical areas (p less than 0.02) in patients operated on with our technique. Maintenance of continuity between the mitral annulus and papillary muscles is expected to have a beneficial effect on postoperative left ventricular performance in spite of increased afterload.