To assess the prevalence of BHV infection in Nepal sera of 2,555 healthy individuals of different age groups from different parts of the country were examined for the markers of the infection. BHsAg and anti-HBs were assayed by R-PHA and PHA methods respectively and anti-HBc by ETA method. Anti-HBc was positive in 43.5 per cent of 2,555 sera of healthy individuals in Nepal. HBsAg was in 0.9 per cent (1.5 per cent in male and 0.5 per cent in female) and anti-HBs in 7.7 per cent (7 per cent in male and 8 per cent in female). The prevalence of HBsAg and anti-HBs was higher in urban than in rural areas, and the highest prevalence of these markers was noted in health care personnels (HBsAg 2.6 per cent and anti-HBs 17 per cent). HBsAg was not detectable in infants and young children, and the highest prevalence rate was observed in 6 to 15 years age group. The main mode of spread of HBV infection in Nepal was the horizontal transmission in pre-adolescent and adolescent children. HBV infection is common in Nepal but the BHsAg carrier rate is much lower than reported from other Asian countries.