Thirty-four minute (less than 5 mm in the largest diameter) and 60 small (6 to 10 mm in the largest diameter) early gastric carcinomas (EGCs) were studied to assess the correlation between gross and histologic features. The characteristic macroscopic feature of many of the histologically differentiated, minute and small EGCs was a depression accompanied by a circumferential elevation of the adjacent noncancerous mucosa. The circumferential elevation was carefully studied histologically. On the other hand, most of the undifferentiated-type minute EGCs included a proliferation of the malignant cells affecting the lamina propria in the middle layer of the mucosa, leaving noncancerous glands and foveolae, and therefore presenting no specific macroscopic change. Most of the undifferentiated-type small EGCs, however, manifested distinct depressions, with or without ulceration; these EGCs were histologically made up of a compact proliferation of carcinoma cells that destroyed both the foveolae and glands. These findings clearly showed the difficulty in detecting the undifferentiated type of minute EGCs and explained the increase in the frequency of the differentiated type in EGCs with a decrease of the size of clinically detectable EGCs. Topographic mapping of the EGCs revealed that the undifferentiated-type minute EGCs that occurred in the middle third of the stomach may well be overlooked.