Hepatitis B infection in the aged can be underestimated as the clinical and serological pictures can be rather peculiar in these subjects. Institutions for the elderly carry an increased risk of HBV spread as do many other closed communities. People from lower socioeconomic class and from countries with a high HBV prevalence are less susceptible to infection as they are already immunized by previous infections. However, epidemics have been described in homes for the aged, mostly from those for wealthy people or from those in low prevalence countries. When infected the elderly tend to develop a subclinical hepatitis detected only by serum analysis. These infections are frequently followed by asymptomatic chronic carriage of HBsAg. This phenomenon may be due to alterations of the immune system in the aged, which is also suggested by the finding of very poor antibody responses to hepatitis B vaccines in the aged. Overt acute hepatitis is infrequent. It usually have a benign course, even if occasionally cholestatic. Very active type B chronic hepatitis is very rare, while most elderly patients with HBsAg-positive chronic liver disease have cirrhosis as the end stage of chronic hepatitis acquired previously.