Rigid sigmoidoscopy is an obligatory part of the routine anorectal examination and enables inspection of the rectum in nearly every case. The extent of bowel examined by flexible sigmoidoscopy is greater and more abnormalities are therefore discovered. With suitable organization, flexible sigmoidoscopy is practicable in the outpatient department. Neither technique examines the large bowel completely so air-contrast barium enema examination with colonoscopy is necessary and should be requested if more proximal disease is thought possible.