Mitral valve replacement with preservation of both leaflets has been reported to have a more significant conservation effect on left ventricular function than offered by mitral valve replacement with preservation of the posterior leaflet alone in patients with mitral regurgitation or double mitral lesions. To compare results of both operative techniques, sixty patients were divided into 2 groups. 30 patients underwent mitral valve replacement with preservation of posterior leaflet (group I) and 30 patients underwent mitral valve replacement with preservation of both leaflets (group II). Rheumatic heart disease was the pathology in all patients. The mean age for group I was 24.1+1.51 years versus 26.1+1.82 years for group II. (90%) of patients in the group I were in NYHA class III and IV preoperatively and in group II (93.3%). 6 patients (20%) in group I had double mitral lesions and 24 (80%) had pure mitral regurgitation. In group II 5 patients (16.7%) had double mitral lesions and 25 (83.3%) had pure regurgitation. All patients were assessed preoperatively using echo-cardiography. Six months postoperatively (85%) in group I were in a symptomatic or mildly symptomatic versus (89.7%) in group II. Techniques of mitral valve replacement preserving both leaflets followed mostly the technique described by Miki et al., 1988. Concomitant surgical procedure included tricuspid valve repair in 7 patients of group I and 6 patients of group II. There were no statistically significant difference regarding the total mortality and morbidity between the 2 groups of patients. Echocardiographic assessment showed statistically significant improvement in both groups as regards left ventricular function and dimensions but it were more pronounced in patients in whom both leaflets were preserved (group II). In addition, there were significant reduction in the left atrial diameter and significant decreased in pulmonary artery systolic pressure postoperatively in both groups. The preservation of the anterior mitral leaflet does not prevent insertion of an adequately sized replacement valve in mitral position and does not lead to left ventricular outflow tract obstruction. Preservation of total mitral valve apparatus is recommended for patients with mitral regurge or double lesions especially in those with poor left ventricular function.