Helicobacter pylori infection of the gastric mucosa causes chronic gastritis and is associated with peptic ulcer disease and gastric carcinoma. These are conditions which usually occur in adult life. However, H. pylori is an infection which is mainly acquired in childhood. The overall prevalence of H. pylori in children is 10% in developed countries but can be as high as 30-40% in children from lower socio-economic groups. In developing countries, the prevalence of H. pylori in children ranges from 80-100%. H. pylori gastritis does not appear to be associated with symptoms in children in the absence of duodenal ulcer disease. H. pylori infection is present in the vast majority of children with duodenal ulcer disease and, as in adults, eradication of the organism results in long-term healing of duodenal ulceration. H. pylori infection acquired in childhood is now considered to be a significant risk factor for the development of gastric carcinoma. The World Health Organization has classified H. pylori as a Group 1 carcinogen. Specific epidemiological questions which need to be answered in children include the age at which infection is acquired, specific risk factors for infection, the mode of transmission and the risk of reinfection following treatment. Recently, a one week treatment regimen using colloidal bismuth subcitrate, metronidazole and clarithromycin has been shown to be effective in treating children, but compliance is important. Currently there are no guidelines on the need to treat children and a consensus is urgently required on this issue.