BACKGROUND In an effort to decrease the death rate from colorectal cancer, a multitude of medical societies and task forces recommend routine screening for colorectal cancer beginning at age 50. Yet, there is no consensus as to the best and most cost-effective screening method. Medicare now pays for screening colonoscopies for its average risk beneficiaries [3]. Many insurance companies, however, will not cover this test in younger patients. We therefore reviewed our institution's colonoscopy experience with asymptomatic 50- to 59-year-olds, with negative fecal occult blood tests and negative family histories. METHODS Between January 1999 and January 2002, 4779 colonoscopies were performed at our institution. The charts for 619 persons 50-59 years of age were retrospectively reviewed, with 91 patients meeting the strict requirements of this study. We defined polyps with high-grade neoplasias as those with villous or tubulovillous components, and cancerous lesions included those with carcinoma in situ. The distal colon was defined as the rectum and sigmoid colon. RESULTS There was a 58% incidence of neoplastic polyps in this younger asymptomatic population. More than 4% of our subjects had high-grade neoplasias or cancerous lesions. In the absence of any distal findings, flexible sigmoidoscopy would have missed up to 38% of these polyps. CONCLUSIONS The findings generally support the recommendations by the American College of Gastroenterology for average-risk patients to preferentially undergo a screening colonoscopy at age 50 in lieu of other methods.