BACKGROUND The present study was designed to study the ability of preoperative serum concentrations of the tumor-associated biomarkers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and adjusted CA19-9 to assess the resectability of advanced gallbladder cancer (GBC). MATERIAL AND METHODS This retrospective study included patients with potentially resectable stage II-IV (AJCC 8th) GBC examined at our institution between January 2012 and December 2016. Receiver operating characteristic (ROC) curve analysis was used to determine the predictive value and optimal cut-off point of tumor-associated biomarkers for curative resection. RESULTS Pathological examination of the 309 patients included in this study found that 169 (54.7%) underwent R0 (curative) resection, whereas 121 (39.2%) underwent R1/2 (non-curative) resection, and 19 (6.1%) were unresectable. The mean serum concentrations of CEA, CA19-9 and adjusted CA19-9 were significantly lower in patients who underwent R0 resection than in the other groups. ROC curve analysis showed that adjusted CA19-9 concentration was better able to predict resectability (area under the curve, 0.774; 95% confidence interval, 0.722-0.826; P<0.001) than total bilirubin, CEA, and CA19-9 concentrations. The optimal cut-off for adjusted CA19-9 concentration was 47.63 U/mL, which had a sensitivity of 69.82%, a specificity of 75%, a positive predictive value of 77.12% and a negative predictive value of 67.31%. CONCLUSIONS Adjusted CA19-9 concentration is an easily calculated parameter superior to CA19-9 and CEA concentrations in predicting the resectability of advanced gallbladder cancer.