A nationwide seroepidemiological study of hepatitis B markers prevalence was conducted in Ethiopia on 5,270 young males from all regions of the country. Overall prevalence rates were 10.8% for HBsAg and 73.3% for "at least one marker positive"; a remarkable geographical and ethnic variability of marker prevalence was observed, reflecting the wide differences existing in Ethiopia in sociocultural environment and activities such as tribal practices and traditional surgery. Sexual practices and medical exposure also play some role as determinants of hepatitis B marker prevalence in Ethiopia. General preventive measures, with particular reference to health education, by affecting incriminating habits and practices could have some impact on infection rates in Ethiopia, in the absence of a vaccination strategy presently unrealistic in this region of the world.