To clarify the presence of depressed adenomas in the human large intestine, a prospective study was performed from January 1986 to December 1987. During these two years, 997 colonoscopies were conducted in patients, excluding cases of familial adenomatosis coli. Of 32 small, depressed lesions biopsied, seven were depressed adenomas, demonstrating that depressed adenomas do exist in the colon and rectum, and can be detected endoscopically. Resembling a sucker, they are easily detected through inflation and deflation.