We assessed the value of liver biopsy in the diagnosis of fever of unknown origin (FUO) in hospital-based patients by a retrospective analysis of all cases (24 cases) seen at the University of Michigan Medical Center over a 5-year period. Based on the findings of a liver biopsy performed in the course of the evaluation of FUO, patients were divided into two groups: a diagnostic group, in which an abnormal liver biopsy was helpful in determining the cause of the FUO, and a nondiagnostic group, which included those who had either normal biopsy results or abnormal biopsy results that did not lead to a final diagnosis. Four patients (16.7%) had diagnostic liver biopsy results (histoplasmosis in three and tuberculosis in one). Physical findings, such as hepatomegaly, and laboratory data, including routine liver chemistries, were not predictive of a diagnostic liver biopsy. Therefore, despite advances in diagnostic technology since this subject was last reviewed, liver biopsy continues to be useful in the diagnosis of FUO. Furthermore, in endemic or borderline endemic areas, histoplasmosis should be considered in the differential diagnosis of FUO, and liver biopsy can be helpful to confirm this diagnosis.