We evaluated clinical effects of mitral valve replacement with preservation of ventricular annular continuity in 53 patients with isolated mitral stenosis and regurgitation. The patients were divided into 3 groups; Group 1: the patients had conventional mitral valve replacement, Group 2: with preservation of posterior leaflet ventricular annular continuity (VAC) (33 patients), and Group 3: preservation of both anterior and posterior leaflet (8 patients). Operative technique was described for pure mitral regurgitation and mitral stenosis. There was one patient died within 30 days operatively in each group. In Group 1 the patient died for poor LV function, in Group 2, the patient died for postoperative GVHD, and in Group 3, the death caused by postoperative LV rupture. We have observed no late death. Minor thromboembolization in early stage were seen in 2 cases of Group 2 and there were no apparent correlation with operative technique. Postoperative cardiac catheterization data (Pulmonary Artery wedge pressure, C.O, LVEF, LVEDV1) showed no significant difference among these 3 groups. Segmental wall contraction in left ventriculography demonstrated good contraction in Group 2 and Group 3 compared with that of Group 1. Left ventricular contraction index with heart rate corrected mean Vcf (Vcfc) and left ventricular end-systolic wall stress (sigma es) relation using two dimensional cardiac echogram demonstrated almost normal range in the groups 2 and 3. These findings suggests that mitral valve replacement with preservation of ventricular annular continuity has beneficial effects on postoperative left ventricular function and requires to be further investigated.