The flexible sigmoidoscope is a flexible fiberoptic or video endoscope designed to examine the mucosal surface of the sigmoid colon and rectum. The flexible sigmoidoscope represents a technologic advancement over the earlier rigid sigmoidoscopes that were hindered by the relatively short length of bowel they could visualize and the rather uncomfortable examination the patient was required to endure in its use. It has clinical usefulness in the evaluation of many disease processes that involve the rectum and sigmoid colon.