Because of the anatomical complexity of the biliovascular structure at the hepatic hilus, surgery for perihilar cholangiocarcinoma is extremely challenging. The standard surgical procedure for this disease includes major hepatectomy combined with caudate lobectomy and extrahepatic bile duct resection. Although radical resection is the only potentially curative treatment option, the extended nature of this surgery carries a high risk for severe postoperative complications, including postoperative liver failure, in which effective treatment is not available. It is particularly important to optimize future liver remnants. The innovation of portal vein embolization has substantially contributed to enhancing the safety of this complicated hepatobiliary resection.