In a retrospective study 157 liver specimens from hemophiliac patients (105 percutaneous needle and 12 wedge biopsies, 40 autopsy specimens) were read blindly and independently by four pathologists on the basis of a computer codable questionnaire asking for evaluation of individual histologic features, classification of the liver disease, and speculation on etiology. The majority of cases had histologic evidence of mild chronic viral hepatitis; 7.6% of all cases were classified as CAH, and an additional 7.6% as CPH by all four interpreters. A large number (40.8%) were on the borderline of CAH and CPH or CLH. These were classified as "possible CAH" because of a diagnosis of CAH by one to three of the pathologists. Although there was therefore some interobserver variability in the diagnostic labels applied to these cases, all four pathologists were strikingly similar in their identification of individual histologic features. Furthermore, on blind rereadings, each pathologist made the same diagnosis in more than 90% of readings. In this retrospective study, serologic data were not available in many cases. Thus, etiologic considerations were based purely on speculation from the histologic appearance. One case was identified as "definite" and 28 of 157 (18%) as "possible" HBV infection. Based on the assumption that some of the individual histologic criteria indeed might be in favor of NANB hepatitis, 21 cases (13%) were considered "definite" NANB, and "possible" NANB was suspected in 107 additional cases (68%). The addition of these figures makes clear that within the limitations of histologic assessment, double infections appear to be frequent in this setting.(ABSTRACT TRUNCATED AT 250 WORDS)