A total of 53 gastric adenomas from endoscopically biopsied gastric mucosa were examined histopathologically. The average age at the time of endoscopic biopsy was 59 years, and gastric adenomas were found to be more frequent in the aged, particularly above the age of 50. The majority of adenomas occurred at the antrum. Concerning the shape of the adenomas, Yamada type II was more frequent (55%). All adenomas were accompanied by varying degree of intestinal metaplasia, and this findings suggest that gastric adenoma develops from intestinal metaplasia. In adenomas with severe atypia (grade III), endocrine cells (argyrophil and argentaffin cells) were markedly decreased or absent. Gastric adenocarcinomas coexistent with adenoma were seen in 5 (9.4%) out of 53 cases, and were more frequent in male than female patients (sex ratio, 4:1) and the average age was 61.4 years. It is suggested that there is a necessity of thorough follow-up study for definitive correlation between gastric adenoma and adenocarcinoma.