Objectives: This study was aimed at assessing whether bypass assisted beating heart surgery reduces pump time, ventilation, and hospital stay, avoids myocardial ischemic and reperfusion injury, gives better long term results over classical cold cardioplegic arrest, for mitral valve replacement in rheumatic mitral valve disease with moderate left ventricular dysfunction. Materials and Methods: 60 patients with rheumatic mitral valve disease with moderate left ventricular dysfunction (Ejection fraction (%) 36.73±4.06), divided into equal and comparable groups, underwent classical mitral valve replacement with St. Jude bileafelet mechanical valve. Group 1 had pumped assisted beating heart surgery and Group 2 had cold cardioplegic arrest. All ventilated, with minimal inotropic support and discharged by 3-10 days. Cardiac enzymes were assessed 6 & 12 hours post declamping. Follow up done by 2D echocardiography on post-operative day 3, 6 months and 1 year. Data was statically evaluated by using Microsoft Excel 2013 version, with values represented as mean±SD. Continuous variables compared with paired student’s t-test. Result: One patient died, due to anticoagulant non-compliance. There was elevation of cardiac enzymes in Group 2, normal in Group 1. Ejection fraction at day 3 and 6 months for Group 1 (47.8±3.25, 53.43±2.6) and Group 2 (39.4±3.1, 40.1±3.5). No further improvement at 1 year. Left ventricular dimensions (mm) at 6 months and 1 year for Group 1 (39.8±2.76/24.6±1.49, 37.8±2.1/24.3±1.32) compared to Group 2 (44.5±5/27.9±4, 42.4±4/27.4±3.7). Ventilation period (hours) and hospital stay (days) for Group 1 (2.95±1.1, 4.1±0.6) compared to Group 2 (7.52±0.9, 8.5±0.8). Conclusion: Mitral valve replacement in rheumatic mitral valve disease with moderate left ventricular dysfunction, bypass assisted beating heart surgery, reduces pump time, ventilation, hospital stay, avoids myocardial ischemic and reperfusion injury and gives better long term results.