An endocrine cell carcinoma of the extrahepatic bile duct in a 79-year-old man is described. The patient had complaints of jaundice and epigastric pain due to a small tumor located at the confluence of the common hepatic duct with the cystic duct. Microscopically, the tumor showed a well differentiated tubular adenocarcinoma and was confined to the mucosa. Numerous tumor cells showed argyrophil and/or argentaffin reactions. Immunoperoxidase staining revealed that the tumor tissue contained somatostatin-, gastrin-and serotonin-immunoreactive cells. From these findings the tumor was diagnosed as endocrine cell carcinoma. Four years later he remains well without any evidence of recurrence or metastasis. The histogenesis of endocrine cells in the biliary tract is briefly discussed.