In order to determine the factors responsible for the differentiation of cytomegalovirus (CMV) hepatitis and Epstein-Barr virus (EBV) hepatitis in previously healthy adults, the clinical features and laboratory data of both types of hepatitis were retrospectively analyzed. CMV hepatitis showed a tendency to increase in our department. In comparison with EBV hepatitis, CMV hepatitis occurred in significantly older hosts than EBV hepatitis. We found that lymphadenopathy, cough and sore throat was more common in EBV hepatitis than in CMV hepatitis. The number of peripheral white blood cell count and atypical lymphocytes, and serum GOT, GPT, LDH and CRP levels of CMV and EBV hepatitis showed no significant differences.