* Helicobacter pylori gastritis progresses to gland loss and intestinal metaplasia in a considerable proportion of colonized subjects. * The progression to atrophic gastritis is a slow process, occurring with an incidence of 1-2% per year. * The progression of chronic H. pylori gastritis is the same in Africa as in Europe and South America. * This supports the concept of H. pylori as a causative factor of pre-neoplastic conditions of the gastric mucosa; other factors must play a modulating role in the progression to cancer. H. pylori gastritis may progress to atrophic gastritis and lead to the development of intestinal metaplasia, dysplasia and eventually gastric cancer in a minority of subjects. The available data on the kinetics of H. pylori gastritis are limited, but nevertheless very consistent. They suggest that the progression to gland loss or atrophic gastritis among H. pylori-positive subjects occurs at a rate of 1-2% per year. As H. pylori gastritis usually persists for life, a considerable proportion of H. pylori-positive subjects thus eventually show signs of gastric gland loss. The majority of these subjects progress to intestinal metaplasia. Despite these consistent findings in different areas of the world, the incidence of gastric cancer is only moderately related to the prevalence of H. pylori. An example is the so-called African enigma, referring to a low incidence of gastric cancer in certain countries of Africa, despite a high prevalence of H. pylori in all age groups. This is not due to differences in progression to atrophic gastritis; other yet unidentified factors therefore must play a role.