The spectrum of liver disease in patients with acquired immune deficiency syndrome (AIDS) and the clinical impact of diagnostic percutaneous liver biopsy in this population were evaluated by a retrospective review of hepatic histology, clinical features and laboratory data in 85 patients (26 biopsies, 59 autopsies). Only 1 (3.8%) biopsy and 9 (15%) postmortem livers were histologically normal. Macrosteatosis and nonspecific portal inflammation were the most common histologic abnormalities. Intrahepatic AIDS-specific opportunistic infections or malignancies were detected in 42% of both biopsy and autopsy groups, with Mycobacterium avium-intracellulare the most frequent pathogen seen. Kaposi's sarcoma, although not detected on biopsy, was the most common postmortem AIDS-related hepatic finding. Intrahepatic lymphoma, cytomegalovirus hepatitis and hepatic mycoses were less frequently observed. In general, hepatic involvement represented part of a previously diagnosed, widely disseminated disease process, and liver biopsy led to new AIDS-specific diagnoses in only two patients. We conclude that while liver biopsy is a useful diagnostic tool in selected patients with AIDS, the information provided by biopsy rarely influences therapy or leads to improved survival.