Background The aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AST/ALT) is an independent predictor of hepatic disease. Objectives To evaluate the association between preoperative AST/ALT and postoperative acute kidney injury in hepatocellular carcinoma patients. Methods A total of 422 hepatitis B- or C- virus-associated hepatocellular carcinoma patients, who underwent hepatectomy between September 2012 and April 2018, were enrolled this retrospective study. From all patients, aspartate aminotransferase and alanine aminotransferase parameters were collected, and the AST/ALT ratio was calculated. For diagnostic criteria of postoperative acute kidney injury, the Kidney Disease Improving Global Outcomes (KDIGO) criteria guidelines were used. Results In 48 patients (11.4%), postoperative acute kidney injury was confirmed. In patients with postoperative acute kidney injury, the mean preoperative serum AST/ALT was significantly higher when compared with patients without postoperative acute kidney injury. After multivariate logistic regression analysis, AST/ALT, haemoglobin, age, hypertension, Child-Turcotte-Pugh classification and the Milan criteria were all confirmed as predictive factors of postsurgical acute kidney injury. We found that an AST/ALT of 1.29 was the best cut-off point for predicting postoperative acute kidney injury. The positive predictive value (23.9%) of the cut-off is actually poor. After matching the propensity score, AST/ALT >= 1.29 was still confirmed as an independent predictor of postoperative acute kidney injury by multivariate analysis. Conclusion Preoperative elevated serum AST/ALT may be a potential independent predictor of postoperative acute kidney injury in hepatocellular carcinoma patients who have undergone hepatectomy. This needs to be tested in further prospective studies.