Introduction Computer tomography colonoscopy (CTC) is an increasingly prevalent procedure for the investigation of colorectal symptoms, or as a component of colorectal cancer screening. It is considered a low risk procedure, however colonic perforation is a recognized significant complication. Case Report We report the case of an 81-year-old female patient who underwent CTC after failed optical colonoscopy as part of routine colorectal cancer screening. Perforation of the rectum with surrounding pararectal air was confirmed on CTC. The patient had minimal symptoms and was treated successful non-operatively with bowel rest and antibiotics. Conclusion Perforation sustained during CTC is an uncommon complication. The incidence of perforation during CTC is still lower than that during optical colonoscopy. In the absence of significant abdominal signs and symptoms, this rare complication may be successfully managed non-operatively.