Purpose: The aims of this study was to compare and evaluate the clinical characteristics, laboratory data, and prognosis for infants under age 1 year with CMV hepatitis and those with viral hepatitis of unknown etiology. Methods: A retrospective study was conducted of infants under age 1 year who were admitted with acute hepatitis. The exclusion criteria consisted of: autoimmune, genetic, metabolic, toxic, HAV, HBV, HCV, toxoplasma, rubella, herpes simplex, and Epstein-Barr virus. The 30 patients included were divided into two groups based on markers for CMV (IgM anti-CMV, CMV PCR in urine, CMV culture in urine). Results: The median age of patients (n=15) was 2.8 months. No other organ involvement was detected in any patient. Peak serum total bilirubin levels (n=4) ranged from 2.6 to 6.7 mg/dL. Peak serum ALT levels ranged from 51 to 1,581 IU/L. The duration of ALT elevation ranged from 1.5 weeks to 26 weeks (median 9 weeks). All had recovered in full without ganciclovir; there were no cases of hearing loss. The median age of controls (n=15) was 2.5 months. Peak serum total bilirubin levels (n=4) ranged from 1.6 to 9.1 mg/dL. Peak serum ALT levels ranged from 26 to 1,794 IU/L. No significant differences were observed between both groups regarding the peak serum ALT levels, peak serum total bilirubin levels, duration of hyperbilirubinemia and ALT elevation. Conclusion: Although it was not possible to differentiate congenital infection with perinatal infection in this study, the prognosis of patients with CMV hepatitis without other organ involvement was good without ganciclovir treatment.