A 70-year-old man was diagnosed with local recurrence 1 and half years after pancreatoduodenectomy for extrahepatic cholangiocarcinoma. Progression of the recurrent tumor involved the portal vein, even though the patient had received chemotherapy (gemcitabine). Although no clinical symptoms caused by portal venous stenosis were found at the time, we performed percutaneous transhepatic portal vein stenting to avoid interrupting chemotherapy. Eighteen months after this procedure, the patency of the portal vein stent was well maintained, and the patient was treated with S-1 chemotherapy continuously without any symptoms related to portal venous stenosis reported. Prophylactic portal vein stenting without clinical symptoms of portal vein stenosis is a useful procedure, not only for palliative care but for improving the prognosis of patients with cholangiocarcinoma by continuous chemotherapy.