Extended right trisegmentectomy with total caudate lobectomy, extrahepatic bile duct resection and lymphadenectomy was performed for a 54-year-old man, who was diagnosed as type IV hilar bile duct carcinoma. After division of the right portal vein and all the portal venous branches to the caudate lobe and the left medial segment, the left hepatic artery and its branches to the segment II and III were dissected from the corresponding bile ducts to about 1 cm beyond the left margin of the umbilical portion of the left portal vein, where the lateral segmental bile ducts were divided after transection of the hepatic parenchyma. All bile duct margins were free from cancer microscopically. To our knowledge this is the first report of extended right trisegmentectomy for hilar bile duct carcinoma, in which the bile ducts of the left lateral segment are divided at the left side of the umbilical portion of the left portal vein. This technique facilitates making the intrahepatic bile duct stumps free from cancer. However, its impact on long-term survival remains to be determined.