Background: Acute kidney injury is a serious complication after coronary artery bypass grafting (CABG). This work aimed to assess the impact of the timing of coronary angiography on kidney function after on-pump coronary artery bypass grafting.Methods: We included 60 patients who underwent elective isolated on-pump coronary artery bypass grafting from 2017 to 2018 at the National Heart Institute and Benha University Hospital. We divided the patients into two groups; group І included 30 patients with coronary angiography performed less than seven days prior to CABG, and Group ІІ included 30 patients who had coronary angiography more than seven days prior to CABG. Postoperative acute kidney injury was defined according to the consensus kidney disease: Improving Global Outcomes Definition and Staging criteria.Results: The mean body mass index was significantly higher in group I (35.89±5.15 Kg/ m² vs. 31.72±4.99 Kg/ m², P = 0.002). The mean preoperative hemoglobin was higher in group II (12.7 ± 1.5 g/dl vs. 13.9 ± 1.5 g/dl, P = 0.004). The frequency of acute kidney damage was higher in patients who had coronary angiography less than seven days before CABG but did not reach a significant level (46.7 % vs. 30%, P =0.184). There was no difference in the creatinine postoperatively between both groups (1.2 ±0.5 vs. 1 ±0.3 mg/dl; p= 0.214).Conclusions: We found no association between the timing of coronary angiography before on-pump coronary artery bypass graft surgery and postoperative acute kidney injury.