Viral hepatitis represents one of the important public health problems throughout the world. However, from the very inadequate and sometimes considerably inaccurate world data on the incidence, severity, and mortality of the disease, only tentative conclusions can be drawn. There is, however, reasonably good evidence derived from HB antigen testing that it is more common in tropical countries than in temperate zones. The need for introducing more complete reporting of hepatitis by age and sex, and differential reporting of hepatitis type A, type B and type unspecified is stressed. In addition, information on the WHO program on hepatitis B is presented.