Background: Renal impairment is associated with increased morbidity and mortality after coronary artery bypass grafting (CABG). Therefore, we aimed to study the risk factors of increased morbidity and mortality after CABG in patients with non-dialysis-dependent mild-to-moderate chronic kidney disease. Methods: This prospective study included 50 patients with non-dialysis-dependent renal impairment (renal disease stage II or III) with off-pump (n= 25) or on-pump (n= 25) CABG. Postoperative outcomes and creatinine levels were compared between both groups. Results: The mean age of all patients was 48.4±12.3 years, and females presented 54% (n= 27). There were no differences in postoperative myocardial infarction (P= 0.923), atrial fibrillation (P= 0.776), blood transfusion (P=0.794), and ICU (P=0.772) and hospital stay (P= 0.698) between groups. Mechanical ventilation was longer in patients with on-pump CABG (16.4 ± 10.9 vs. 6.1 ± 3.2 hours; P˂0.001). Creatinine levels were significantly lower in patients who had off-pump CABG (P˂0.001). The cumulative mortality hazard increases to 56.7% in patients with preoperative creatinine levels above 2 mg/dl.   Conclusion: High preoperative creatinine levels could increase mortality in patients undergoing CABG. Off-pump CABG could be a better approach in patients with mild to moderate renal dysfunction.