This study was undertaken to determine the seroprevalence of H.pylori in asymptomatic children and compare it with that seen in the asymptomatic adult population from south India. One hundred and five children and one hundred adults admitted to the wards for conditions other than gastrointestinal disorders were included for this study. H.pylori status was determined by ELISA for IgG. The prevalence of H.pylori in children of various ages varied from 44% to 46% with an overall prevalence of H.pylori in children of 45%. 67% of adults were infected with H.pylori which was significantly higher than children (P = 0.002). The prevalence of H.pylori increased markedly with age with the maximum colonization (74%) occurring in young adults (16-30 years). The antibody levels too followed a similar pattern. In conclusion, it was seen that almost half the children in south India acquire H.pylori infection early in life which increases slowly and steadily with a peak prevalence in the young adults. Gender does not affect the prevalence in children and adults. As age advances further there is a slight decline in the prevalence of H.pylori infection. The immune response reflected by the levels of the antibody levels also follows the same pattern.