Colonoscopy is a safe and effective way to check the mucosa of the large intestine and rectum. It can not only diagnose but also remove polyps. Most of the colonscopy can be performed in outpatient clinics with only a little inconvenience and discomfort. The most common complications of colonoscopy are colon bleeding and perforation. Incarceration of the colonscopy in a sliding inguinal hernia is very rare and a potentially fatal complication of colonoscopy. We report a 70-year-old male patient who had an bilateral inguinal hernia but only repaired hernia on the right side and no repair on the left side. This time, the colonoscope incacreated into the hernia sac and the colon and required surgery to successfully remove the colonoscope from the anus. There should be taken complete medical history and physical examination before colonoscopy. Although other complications are rare, it is still necessary to keep in mind to diagnose and treat in time.