Based on reported success and safety, 1121 sigmoidoscopies were performed in 964 patients seen privately by one surgeon, as a routine office screening procedure, using the flexible 60-cm sigmoidoscope instead of the rigid 25-cm instrument. The doubling of the distance that was examined doubled the diagnostic yield for neoplasia and inflammatory bowel disease, specific or nonspecific. As compared with barium-enema examinations, the yield was even greater: 5:1 for neoplasia, 7:1 for inflammation, 3:1 for polyps greater than 1 cm, and 5:1 for false-negative, false-positive, or equivocal x-ray findings. No serious complications were encountered in any of the examinations including 72 polypectomies performed in the office. The study supports flexible fiberoptic sigmoidoscopy as a major screening tool for individuals in private practice in truly evaluating the interior of the lower 60-cm of the colorectum for neoplasia and for the diagnosis and monitoring of bowel disease or neoplasia confined to that area.