A review is done on the evidence in favor of a link between Helicobacter pylori infection and gastric cancer of the intestinal type. In countries at high risk of gastric cancer, like Perú, Hp infection begins early in life and is highly frequent and persistent. When Hp colonizes the gastric mucosa, it causes active chronic gastritis. Initially, the gastritis is of the superficial type. With time, and probably as a result of the concurrent action of nutritional, epidemiologic and immunologic modulating factors, chronic superficial gastritis may give rise to a progressive gastric pathology that leads to gastric premalignant lesions (chronic atrophic gastritis, intestinal metaplasia and dysplasia of the gastric mucosa) and increases the predisposition to gastric cancer. The principal modulating factors are described. The epidemiology of gastric premalignant lesions in Perú is also described. Finally, a discussion is done on the effect that eradication of Hp infection might have on the prevalence of gastric cancer.