Abstract Objective: Acute kidney injury (AKI) is one of the most important complications after coronary artery bypass grafting (CABG) procedure. Serum albumin, which is an acute phase reactant, is suggested to be associated with AKI development subsequent to various surgical procedures. In this study, we research the relation between preoperative serum albumin levels and postoperative AKI development in diabetes mellitus (DM) patients undergoing isolated CABG. Methods: We included a total of 634 diabetic patients undergoing CABG (60.5±9.1 years, 65.1% male) into this study, which was performed between September 2009 and January 2014 in a single center. The relation between preoperative serum albumin levels and postoperative AKI development was observed. AKI was evaluated and diagnosed using the Kidney Disease: Improving Global Outcomes (KDIGO) classification. Results: AKI was diagnosed in 230 (36.3%) patients. Multiple logistic regression analysis was performed to determine the independent predictors of AKI development. Proteinuria (odds ratio [OR] and 95% confidence interval [CI], 1.066 [1.002-1.135]; P=0.043) and low preoperative serum albumin levels (OR and 95% CI, 0.453 [0.216-0.947]; P=0.035) were found to be independent predictors of AKI. According to the receiver operating characteristic curve analysis, albumin level <3mg/dL (area under the curve: 0.621 [0.572-0.669], P<0.001) had 83% sensitivity and 10% specificity on predicting the development of AKI. Conclusion: We observed that a preoperative low serum albumin level was associated with postoperative AKI development in patients with DM who underwent isolated CABG procedure. We emphasize that this adjustable albumin level should be considered before the operation since it is an easy and clinically implementable management for the prevention of AKI development.