Incidence and epidemiological features of acute hepatitis types A, B and non-A non-B have been evaluated in 332 consecutive patients hospitalized in Padova, Italy. Hepatitis B was diagnosed in 59% of cases and was frequently related to drug addition, health care work and household contact with HBsAg-positive subjects. Hepatitis A represented 22% of cases and its peak incidence occurred in the second decade. Non-A non-B hepatitis affected 15% of patients including not only transfusion or drug related forms, but also sporadic cases that prevailed among elderly women.