The etiological types and some features of 163 in-patients with acute viral hepatitis in Xi'an in China are reported. Hepatitis A (HA) accounted for 89.2% in the age group 0-15 years, whereas hepatitis B (HB) mainly occurred at the age of 16 to 30 and non-A, non-B hepatitis 31 to 50. This is different from the age distribution in western countries. The cause of the difference is discussed. The transmission factors of NANB hepatitis might be different from those of HA and HB. Fever was more often seen in HA than in HB and NANB, while the maximal bilirubin was higher in HB than in NANB. Hepatic dysfunction of all three types of hepatitis seemed to be closely associated with the age of the patients. Of ten cases with fulminant hepatitis, none was due to hepatitis A; nine were adults.