Data on patients with extrahepatic bile duct carcinomas recorded in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were reviewed. We analyzed the records of 1766 patients reported during a 10-year period (1977-1986). These tumors occurred primarily in older age groups and were slightly more common in males. Histologic grade, histologic types, and stage of disease are useful prognostic indicators. The 5-year survival rate for patients with Stage I disease was 11%. Although carcinomas of the extrahepatic bile ducts are better differentiated than carcinomas arising in the gallbladder, they have a less favorable prognosis.