The submitted review is devoted to the problem of chronic víral hepatitis B focused on epidemiology, clinical and laboratory findings, histologickl findings, the course and prognosis. The author explains the term pre-core or e-minus mutant of the hepatitis B virus, when the infection by this mutant is associated with a higher viraemia, more aggressive form of chronic hepatitis which even afier successful treatment with interferon alpha usually relapses. Next the author describes three stages of chronic hepatitis B, i.e. the stage of víral replication, the stage of seroconversion and the stage of víral latency. He explains also HBsAg carriership and the interpretation of some problematic serological findings. Attention is also paid to the main extrahepatic manifestations in chronic infections with the hepatitis B virus.

        Key words: chronic víral hepatitis B, HBsAg carriership, e-minus mutant of hepatitis B virus, pre-core mutant of hepatitis B virus