Helicobacter pylori causes chronic active inflammation of the gastric mucosa in the majority of infected patients. In a considerable number of them, this will eventually lead to a loss of gastric glands, and thus the establishment of atrophic gastritis. This is associated with the development of intestinal metaplasia and dysplasia. These consecutive conditions increase the risk for gastric cancer. particularly of the intestinal type. We reviewed the evidence that H. pylori plays an important role in this sequence of events that can lead to gastric cancer. This paper focuses on the difficulties in staging atrophic gastritis, the incidence and prevalence of this condition and the relation with H. pylori infection. Furthermore, it describes the evidence for the role of this organism and gastric mucosal atrophy in the aetiology of gastric cancer and focuses on the life-time incidence of gastric cancer in the presence of this bacterium.