Computed tomography colonography, also termed virtual colonoscopy, is a new imaging method to investigate the colon, which may be a potential alternative to the conventional endoscopic colonoscopy in some cases. The high safety profile of this imaging method was considered as an additional advantage of this procedure. A case of colonic perforation in computed tomography colonography is presented, highlighting a potential risk related to this procedure. It is assumed that perforation was the result of overinflation of air into an obstructed colon caused by a lesion at the rectosigmoid junction. Thus, it is suggested that in such cases, air insufflation should be gradual, thereby minimizing the risk of perforation.