A 65-year-old woman was admitted to our institution with sonography results indicating a caudate lobe mass. CT showed a large low-density mass in the caudate lobe, extensively involving the inferior vena cava and main portal vein. Moderately differentiated adenocarcinoma was found on transcutaneous biopsy. We therefore regarded this tumor as a severe locally advanced hilar cholangiocarcinoma and initiated gemcitabine/cisplatin combined chemotherapy. The tumor gradually reduced in size. However, after 28 courses of treatment, CT showed persistent tumor invasion in the left trunk of the portal vein and inferior vena cava invasion in succession in the middle; the tumor had not yet invaded the left hepatic vein. Owing to myelosuppression and general malaise, it was difficult to continue chemotherapy. After 32 courses of treatment, the patient underwent a left trisegmentectomy with combined resection of the portal vein and inferior vena cava. Postoperative microscopic findings revealed no apparent invasion of the tumor in the inferior vena cava, thus suggesting successful R0 resection. The patient is alive without recurrence 18 months postoperatively.