Arteriovenous malformation is well known cause of lower gastrointestinal bleeding in elderly patients. This is relatively uncommon in people younger than 50 years of age. Endoscopically, it generally appears as bright red flat or elevated bright red lesion. A polypoid appearance is extremely uncommon. We report a case of large polypoid arteriovenous malformation of colon in 81-year-old male patient. He has complained of hematochezia for 4 days. During colonoscopy, a 3.5 cm sized semipedunculated polypoid mass in the proximal transverse colon was detected. For prevention of bleeding, detachable snare was applied and biopsy was done. 3 days later, follow up colonoscopy was done. There was no hemorrhege. We performed endoscopic mucosal resection. Polypoid arteriovenous malformation of colon was comfirmed by microscopic findings. Histologically, section of excised polyp shows ulceration, hemorrhage and the dilated, irregularly thick walled blood vessels in the mucosa and submucosa. (Intestinal Research 2004;2:36-39)