Introduction: Cardiac reperfusion injury is a well-described complication occurringafter ischemia or following cardioplegic arrest. The primary aim of this study was to evaluateand compare safety of Mitral valve replacement on beating heart without using cross clampwith the conventional Mitral valve replacement. Material and methods: It was a retrospectiveobservational study for study duration from 2012-2014. A total of 50 patients were randomlyselected and were divided in 2 groups, 25 patients in each group. This study was conductedat the Department of Cardiovascular Surgery of Choudhry Pervaiz Elahi Institute of Cardiology,Multan. We divided the patients in two groups. All operations were carried out by team led bya consultant surgeon in our institution. Results: Our patients had the age range from 12 to 65years (Mean ages=32.5 years ± 13.9000) the mostly this study included males 60 %. The studyincluded Group A and Group B (beating heart versus conventional heart surgery) both groupscontained randomized controlled patients with purposeful sampling. Minimum operative time100 minutes or maximum operative time 160 minutes (Mean 195± 95.75) The P value remainednon significant that P <0.001. The CPB time was 22 to 388 minutes (104.8 ± 97.4. Cross Clamptime, ICU stay intubation time, drainage, inotrope remained almost same in both groups. With P<0.001 Outcome variables of the patients. Discussion: The hazards of cardiopulmonary bypassand Cardioplegia are well known. Various studies have demonstrated decreased accumulationof extra cellular fluid, diminished lactate production and greater preservation of high energystores when a strategy of myocardial protection simultaneous antegrade/ retrograde continousnormothermic, normokalemic blood perfusion was used. These findings were the basis forusing beating heart technique for mitral valve replacement, Aortic cross-clamping, Cardioplegia,and reperfusion injury leads to myocardial ischemia and is a critical issue in mitral valve surgerydespite novel approaches to myocardial protection. Myocardial edema induced by the lack ofmyocardial contractions and impaired lymphatic flow due to Cardioplegia in the heart remainingin diastole is another cause of myocardial dysfunction. Conclusions: Outcomes obtained usingthis strategy of myocardial protection seem to compare favorably to those of historical series inwhich conventional myocardial protection with cardioplegic arrest were used.