Our purpose was to assess the performance of CT colonography (CTC) in patients older than 60 years who were referred because colonoscopy was contraindicated or incomplete. Over a 2-year period, 61 patients underwent CTC at our institution, 42 of whom (26 women, 16 men) were 60 years old or older (range, 60-87 years; mean age, 71 years). After 24-48 hours of ingesting only clear liquids and after colonic cleansing, fecal tagging, and automated CO2 insufflation, patients were scanned using a 16-MDCT scanner. Images were obtained with the patient in the supine and prone positions and as needed in the right or left decubitus position. Axial 2D and 3D endoluminal views were evaluated on a dedicated workstation. Contraindications to colonoscopy in 12 (29%) of the 42 patients were as follows: anticoagulation (n = 8), increased anesthesia risk (n = 3), and poor tolerance for colonoscopy preparation (n = 1). Incomplete colonoscopy in the other 30 patients (71%) was due to diverticular disease (n = 10), colonic redundancy (n = 10), adhesions (n = 3), residual colonic content (n = 3), sigmoid stricture (n = 1), ventral hernia (n = 1), and unknown cause (n =2). No complications were observed. Optimal distention of the entire colon was achieved in 38 patients (90%). Thirty-nine (93%) of the 42 patients had abnormal findings: diverticular disease (n = 25), one or more polyps (n = 22), a mass lesion (n = 1), a lipoma (n = 1), and inflammatory stricture (n = 1). Extracolonic findings potentially requiring further evaluation or treatment were observed in 26 patients (62%). CTC using CO2 insufflation was well tolerated and successful in imaging the entire colon in most of the 42 patients, despite the presence of sigmoid diverticular disease or colonic redundancy.