The occurrence of colon cancer in 1 patient with acromegaly prompted a study of an additional 12 patients with acromegaly. In addition to the index case, 1 patient was retrospectively discovered to have colon cancer, and 1 was found to have colonic adenocarcinoma in the course of the study. One patient had a presumptive sigmoid polyp shown by barium enema but refused further studies. Eight patients received colonoscopy. Two patients had adenomatous polyps and 1 had two hyperplastic polyps. This study supports previously published data on the occurrence of colon polyps in patients with acromegaly and suggests that the incidence of colon cancer is much higher than that expected by chance.