In a sample of inhabitants of the Arsi region of Ethiopia prevalence of hepatitis B is around 80% in the age group 20-24. In addition to age, sex and size of family, exposure to tribal practices is a determinant of seropositivity in this group accounting for as much as 20% of the total burden of the infection. Waiting for a mass vaccination campaign, presently unrealistic in this area of the world, health education, as part of a comprehensive primary health care program, has to be considered as a potentially effective preventive tool.