We have developed a magnified endoscopic technique for observing the microvascular architecture within the gastric mucosa in units as small as capillary and we have reported the characteristic findings of the microvascular architecture in both normal gastric mucosa and early gastric cancer. The findings in the normal stomach were different depending on the section of the stomach. The body mucosa demonatrated a regular honeycomb-like subepithelial capillary network pattern with a collecting venule, while the antral mucosa demonstrated a regular coil-shaped subepithelial capillary network pattern. The magnified endoscopic findings of early gastric carcinoma were different depending on the types of histological differentiation. The characteristic findings of differentiated carcinoma were (1) the presence of a demarcation line; (2) the disappearance of the regular subepithelial capillary network pattern; and (3) the presence of an irregular microvascular pattern. The findings of undifferentiated carcinoma showed only a reduction in or else the complete disappearance of the regular subepithelial capillary network pattern. In clinical practice, the magnified endoscopic findings of differentiated carcinoma are useful both for determining the margin of early gastric cancer and for making a differential diagnosis between gastritis and gastric cancer in the case of flat reddened lesions. The microvascular architecture as visualized by magnified endoscopy could be a new diagnostic system for the endoscopic diagnosis of early gastric cancer.