One hundred consecutive patients with blood cultures positive for microbial growth were prospectively surveyed for the presence of hepatic abnormalities and clinical evidence of infection. Complete data for 82 patients were available for analysis. Fifty-four percent had elevated bilirubin levels, and 34% had total bilirubin values of greater than or equal to 2.0 mg/dl. The levels of total bilirubin were disproportionately elevated compared with those of aspartate aminotransferase, alkaline phosphatase, and cholesterol. Nine of the 23 patients with elevated bilirubin levels had an increase in serum bilirubin one to nine days before their initial positive blood culture. Disproportionate elevations of direct and total serum bilirubin values compared with values for other liver-function tests appear to be associated with bacteremia in adults more frequently than previously recognized and may have some predictive value in such patients.