Cat scratch colon (CSC) is an entity characterized by bright red linear tears which appear in the colonic mucosa during colonoscopy. Although they do not generally have clinical implications, cases of secondary pneumoperitoneum have been reported. To date, the prevalence, associated diseases, and factors that determine the appearance of CSC have not been adequately determined. We report a series of 20 cases of CSC found in 10715 consecutive colonoscopies. Demographic data, indication for the colonoscopy, endoscopy findings, and complications related to the procedure were recorded. Older age and male sex were significantly associated with CSC. In 15 of the 20 cases the CSC was related to diversion colitis, and 5 cases appeared in patients with collagenous colitis. In patients with diversion colitis, the longer the time elapsed since surgery, the greater the risk of these lesions occurring. None of the patients with CSC had complications related to the colonoscopy.