Viral hepatitis is a major public health problem, occurring endemically in all areas of the world. The prevalence of the disease is influenced by numerous factors which may be able to modulate its onset. Study of the epidemiology of viral hepatitis in different geographical, ethnic, social and genetic groups as well as immunological and individual factors has contributed much to our understanding of the disease. Hepatitis viruses are classified into A (infectious hepatitis), B (serum hepatitis) and non-A, non-B. The transmission of hepatitis B virus (HBV) is a potential hazard in dental practice. A number of reports suggest a significantly higher incidence of hepatitis among dentists than in the general population and also higher rates of hepatitis in certain specialists, especially oral surgeons, periodontists and endodontists, than in general dentists. Vectors of infection with HBV in dental practice are blood, saliva and nasopharyngeal secretions. The incidence of hepatitis B in dental practitioners is influenced by the exposure to infection, the type of practice, the number of years of professional experience and antibody response. HBV may be spread by dentists and dental students, by dental auxiliaries and by other personnel closely associated with clinical practice, who are antigen positive carriers but have no clinical symptoms. Therefore, dentists and their staff should know well the risk of infection from their patients, the risk of cross-infection between patients, and the risk of infecting each other.