Clinical observations suggest a recent increase in intrahepatic biliary tract malignancies. Thus, our aim was to determine recent trends in the epidemiology of intrahepatic cholangiocarcinoma in the United States. Reported data from the Surveillance, Epidemiology, and End Results (SEER) program and the United States Vital Statistics databases were analyzed to determine the incidence, mortality, and survival rates of primary intrahepatic cholangiocarcinoma. Between 1973 and 1997, the incidence and mortality rates from intrahepatic cholangiocarcinoma markedly increased, with an estimated annual percent change (EAPC) of 9.11% (95% CI, 7.46 to 10.78) and 9.44% (95%, CI 8.46 to 10.41), respectively. The age-adjusted mortality rate per 100,000 persons for whites increased from 0.14 for the period 1975-1979 to 0.65 for the period 1993-1997, and that for blacks increased from 0.15 to 0.58 over the same period. The increase in mortality was similar across all age groups above age 45. The relative 1- and 2-year survival rates following diagnosis from 1989 to 1996 were 24.5% and 12.8%, respectively. In conclusion, there has been a marked increase in the incidence and mortality from intrahepatic cholangiocarcinoma in the United States in recent years. This tumor continues to be associated with a poor prognosis.