OBJECTIVE:Postoperative acute kidney injury is an important problem that can occur after coronary artery bypass graft operations, and it is important to identify risky patient groups preoperatively. This study aimed to investigate the importance of preoperative syndecan-1 levels in predicting acute kidney injury after elective coronary artery bypass graft operations accompanied by cardiopulmonary bypass. METHODS: Patients who underwent coronary artery bypass graft operation in our clinic between March 1 and May 10, 2022, were included in this prospective study. Patients who did not develop acute kidney injury in the postoperative period were recorded as group 1 and patients who developed it were recorded as group 2. RESULTS: A total of 79 patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass were included in the study. There were 55 patients in group 1 and 24 patients in group 2. There was no difference between the groups in terms of age, gender, diabetes mellitus, body mass index, smoking, and hyperlipidemia rates. In multivariate logistic regression analysis, increased blood product use (odds ratio 1.634; 95%CI 1.036-2.579; p=0.035), preoperative high creatinine (odds ratio 59.387; 95%CI 3.034-1162.496; p=0.007), and high syndecan-1 (odds ratio 1.015; 95%CI 1.002-1.028; p=0.025) were independent predictors of acute kidney injury. CONCLUSION: This study revealed that elevated preoperative syndecan-1 is associated with acute kidney injury after isolated coronary artery bypass graft accompanied by cardiopulmonary bypass and has prognostic utility independent of other recognized risk factors.