BACKGROUND: Despite many population-based epidemiological studies of Helicobacter pylori prevalence in different parts of the world, Russia still represents a 'blank spot' in this map. The aims of the present study were to evaluate the seroprevalence of H. pylori infection among the population of Siberia and to assess whether there is an association between abdominal symptoms and H. pylori positivity in our population. METHODS: Six hundred and forty-nine adults from five regions of Siberia and the Far East, and 79 children and adolescents from Novosibirsk participated in the study. Antibodies against H. pylori (IgG) were detected in serum using ELISA. RESULTS: The total percentage of infected adults varied from 70% to 92% depending on the region, and was somewhat lower in three populations living to the north of the 60th latitude compared with those under the 60th latitude. A lack of association was found between the presence of H. pylori and the gender, age and abdominal symptoms. Almost maximum prevalence of H. pylori infection occurred by 30 years of age with only a minor increase in older age groups. Half the children were infected with H. pylori by the age of 15. CONCLUSIONS: Helicobacter pylori infection is widespread among the Siberian populations with some trend in its prevalence to decrease northward. In Siberia age-specific prevalence rates of H. pylori infection are similar to those usual for developing countries.