Background: The Bismuth-Corlette (BC) classification is used to categorize hilar cholangiocarcinoma by proximal extension along the biliary tree. As the right hepatic artery crosses just behind the left bile duct, we hypothesized that BC Ⅲb tumors would have a higher likelihood of local unresectability due to involvement of the contralateral artery.Methods: A retrospective review of a prospectively maintained database identified patients with hilar cholangiocarcinoma taken to the operating room for intended curative resection between April 2008 and September 2016. Cases were assigned BC stages based on preoperative imaging. Results: Sixty-eight patients were included in the study. All underwent staging laparoscopy after which 16 cases were aborted for metastatic disease. Of the remaining 52 cases, 14 cases were explored and aborted for locally advanced disease. Thirty-eight underwent attempt at curative resection. After exclud- ing cases aborted for metastatic disease, the chance of proceeding with resection was 55.6％ for BC Ⅲb staged lesions compared to 80.0％ of BC Ⅲa lesions and to 82.4％ for BC Ⅰ-Ⅲa staged lesions ( P < 0.05). About 44.4％ of BC Ⅲb lesions were aborted for locally advanced disease versus 17.6％ of remaining BC stages. Conclusions: When hilar cholangiocarcinoma is preoperatively staged as BC Ⅲb, surgeons should antici- pate higher rates of locally unresectable disease, likely involving the right hepatic artery.