Vascular ectasia is a well-known cause of lower gastrointestinal bleeding in the elderly. Endoscopically, it usually appears as a flat or elevated bright red lesion. We report on an extremely rare case of a large, pedunculated, polypoid vascular ectasia in an asymptomatic patient. A large pedunculated polypoid mass in the sigmoid colon was observed on colonoscopy during a regular health check-up, and a polypectomy was performed using a detachable snare. In histology, vessels with massive dilation were found mainly in the submucosa, which was consistent with vascular ectasia.