The results are reported of an epidemiological assessment of 94 patients hospitalised with diagnosed acute viral hepatitis in the Infectious Disease Division of the S. Spirito Hospital, Casale Monferrato in the period march 1 1981, april 30 1982. Hepatitis was found to occur most frequently among young (under 30) males. There were more positive than negative HBsAg cases, most of the latter arising in heroin addicts.