Introduction: This study is aimed to study the effect of mean arterial pressure (MAP) on renal function of adult patients undergoing cardiac surgery with cardioplulmonary bypass (CPB). Methods: A retrospective observational study was conducted and included a total of 99 patients who had undergone cardiac surgery under CPB. Renal dysfunction was assessed using RIFLE criterion during early post operative period. Patients were divided into those whose MAP was <50mmHg second group of patients where MAP was more than 50 mmHg. Total CPB time & aortic cross time (ACC) were recorded during surgery and post-operatively renal parameters (creatinine & urine output), blood transfusions requirements, hospital stay and mortality associated with renal dysfunction and prolonged CPB & ACC were studied. statistical analysis of observed parameters was done with p-value <0.05 considered significant. Results: Pre-operative patient demographics were recorded. Coronary artery bypass surgery (CABG) were the maximum cases performed followed by valve replacement surgeries. There was significant association between MAP <50mmHg to renal dysfunction (p<0.001), and between mortality to renal dysfunction (p<0.001). It was observed that prolonged CPB time & ACC time was statistical significantly associated with renal dysfunction (p=0.019; 0.023), CSA-AKI (p=0.007; 0.021), blood transfusions (p=0.04; 0.283) & mortality (p<0.001; 0.005). Conclusion: MAP of more than 50 mmHg is desirable and recommended to prevent cardiac surgery associated acute renal injury during CPB and every effort should be made to shorten CPB time & ACC time to improve post-operative results.