Ninety-three consecutive orthotopic liver transplantations in 78 patients were followed prospectively to study the incidence of cytomegalovirus (CMV) hepatitis. CMV hepatitis occurred in 13 (17%). The diagnosis was established by both histology and culture in 5, only by histology in 6, and only by culture in 2. All 13 patients had CMV viruria and 9 had viremia at diagnosis. CMV hepatitis developed in 64% of CMV-seronegative (pretransplantation) patients who received a liver from a CMV-seropositive donor, compared with 3% or 6% of CMV-seropositive patients who received a liver from a CMV-seronegative or CMV-seropositive donor, respectively (P less than .001). CMV hepatitis was not a cause of fulminant or irreversible liver dysfunction in any of the 13 cases. Ganciclovir was administered to 6 of the 13 patients and was associated with clinical and virologic cure in 5. CMV hepatitis was self-limited in patients not treated with ganciclovir (illness less severe). The presence of inclusions within the liver tissue correlated with active disease.