Magnifying endoscopy has been developed to visualize the microstructure of gastrointestinal surface mucosa and mucosal vascularity. Magnifying endoscopy is starting to play an important role in the diagnosis of upper gastrointestinal diseases: Barrett's esophagus, atrophic gastritis, Helicobacter pylori-induced gastritis, gastric neoplasm. Chromoendoscopy in conjunction with magnifying endoscopy improves diagnostic accuracy and allows the early detection of premalignant and malignant lesions. Standardization of the procedural methodology and consensus terminology of the mucosal patterns are crucial.