Gastric cancer is an important worldwide health problem and causes considerable morbidity and mortality. It represents the second leading cause of cancer-related death worldwide. A cascade of recognizable precursor lesions precedes most distal gastric carcinomas. In this multistep model of gastric carcinogenesis, Helicobacter pylori causes chronic active inflammation of the gastric mucosa, which slowly progresses through the premalignant stages of atrophic gastritis, intestinal metaplasia and dysplasia to gastric carcinoma. Detection and treatment of premalignant lesions may thus provide a basis for gastric cancer prevention. However, at present, premalignant changes of the gastric mucosa are frequently disregarded in clinical practice or result in widely varying follow-up frequency or treatment. This review provides an overview of current knowledge on detection, surveillance and treatment of patients with premalignant gastric lesions, and identifies the uncertainties that require further research.