From December 2000 to April 2001, 859 patients were examined with coloscopy in our endoscopy centre and 188 cases of adenoma were diagnosed. Among the 188 patients, 7 were found with serrated adenoma that had been confirmed pathologically, including 6 male and 1 female patients, aged 32 to 53 with an average of 44.7 years. All the 7 cases were identified as having single focal lesion, among which 3 were found in the rectum, 1 in the transverse colon, 2 in the ascending colon and 1 in the cecum. The diameter of the lesions ranged from 8 to 27 mm with an average of 15.4 mm.