Background: Acute kidney injury (AKI) is described as an abrupt worsening of renal function, with a rise in serum creatinine levels and slow urine production. There is a high possibility to develop AKI about 30% after coronary artery bypass grafting (CABG) operation, 2% of them may need hemodialysis, which related with higher morbidity and mortality. Objective: This study aimed to compare incidence of AKI between on pump versus off pump CABG. Patients and Methods: A randomized retrospective observational comparative study that was done in Benisuef University. Patients' data was gathered from those who underwent CABG surgery through 5 years through the period from March 2017 to March 2022, where 100 patients had ischemic heart disease, underwent isolated CABG operation whether on pump or off pump in the department of Cardiothoracic Surgery, Faculty of Medicine, Benisuef University. Of them 50 had on pump CABG included in group A and the other 50 had off pump CABG included in group B. AKI incidence was compared between both groups. Results: There was no statistically significant difference between both groups regarding patients' demographics, baseline clinical data and preoperative investigations results. Also, there was no statistically significant difference between both groups regarding operative data including urine output, intra-aortic balloon (IAB) pump and inotropic support usage intraoperatively. But, there was a statistically highly significant difference (> 0.01) between both groups regarding more intraoperative blood loss, blood transfusion, total surgery time and more arterial grafts other than left internal mammary artery (LIMA) that were used in group A. AKI occurred in 3 (6%) patients in group A of them 2 (4%) patients required temporary dialysis in the ICU and no patient required permeant dialysis in comparison with group B where 2 (4%) patients had AKI of them 1 (2%) patient required temporary dialysis in the ICU and no patient required permeant dialysis. So, there was no statistically significant difference between both groups. Regarding other postoperative morbidities, there was no statistically significant difference between both groups. Also, there was no difference in mortality where there was 1 (2 %) mortality in group A and 1 (2%) mortality in group B Conclusions: There was no difference between on pump and off pump technique regarding the incidence of AKI and temporary and permanent dialysis. Also, there was no difference in the incidence rate of postoperative morbidity and mortality between both groups.