Clinical course, morphologic changes, immunohistochemical localization of HBV-associated markers (HBsAg, HBcAg), and serum HBV-DNA production are described in 2 chronic HBsAg carriers superinfected with HAV and hepatitis non-A, non-B virus. Our data suggest that the superinfections do not cause more severe disease and do not influence the clinical course of the HBsAg chronic carriers. Our observations indicate that a careful diagnosis of hepatocytolysis is necessary in HBV chronic infection, in order to discriminate causes that are able to induce severe damage in underlying disease.