Hepatic histologic materials (biopsy or autopsy) and associated clinical data from 155 hemophiliacs were collected by an ad hoc hemophilia study group and analyzed retrospectively in an effort to determine the spectrum of liver disease in this population and to examine the relationship between the severity of liver disease and treatment history. Clinical information on the frequency of complications from 126 biopsies in 115 hemophilic patients provided a unique opportunity to assess the safety of liver biopsy in such patients. The incidence of cirrhosis (15%) and chronic active hepatitis (7%) was lower than previously reported. The frequency of severe liver disease (chronic active hepatitis or cirrhosis) in patients receiving large pooled concentrates was no greater than in patients treated principally with cryoprecipitate or plasma. The risks of liver biopsy in this setting are relatively high: clinically significant hemorrhage followed 12.5% of the procedures.