Helicobacter pylori infection is the world's most common chronic infection in humans and is the cause of most gastritis cases. This infection is accepted as the etiology of the majority of peptic ulcers. It has been implicated as a significant contributing factor in the development of gastric malignancy – both gastric MALT lymphoma and gastric adenocarcinoma. Both endoscopic and non-endoscopic tests are available for accurate diagnosis of the infection. Several multi-drug regimens are useful for effective eradication of the infection. Strategies have been developed for managing patients with gastric MALT lymphoma. Criteria to identify populations with increased risk for gastric malignancy are being developed. H. pylori induces gastritis; it is also involved in both apoptosis and cellular proliferation. The role of H. pylori infection in the pathogenesis of premalignant lesions, altered gastric acid secretion, and significant clinical presentations is the subject of numerous studies worldwide.