&NA;Since its introduction into clinical medicine, flexible fiberoptic colonoscopy has had a great impact on diagnosis and management of diseases of the colon and rectum. There are three mechanisms responsible for colonoscopic perforation: specifically, mechanical perforation directly from the colonoscope or a biopsy forceps, barotrauma from overzealous air insufflation, and, finally, perforations that occur during therapeutic procedures. Perforation of the colon, which requires surgical intervention more frequently than bleeding, occurs in less than 1 percent of patients undergoing diagnostic colonoscopy and may be seen in up to 3 percent of patients undergoing therapeutic procedures such as polyp removal, dilation of strictures, or laser ablative procedures. Management of colonic perforation secondary to colonoscopy remains a controversial issue in that it can be effectively managed by operative and nonoperative measures. If a perforation does occur, signs and symptoms that the patient will experience will be related to both the size and site of the perforation, adequacy of the bowel preparation, amount of peritoneal soilage, underlying colonic pathology (where a thin walled colon from colitis or ischemia, for example, may result in a larger perforation than a healthy colon), and, finally, overall clinical condition of the patient. Radiology often establishes diagnosis. Plain films of the abdomen and an upright chest x‐ray may reveal extravasated air confined to the bowel wall, free intraperitoneal air, retroperitoneal air, subcutaneous emphysema, or even a pneumothorax. A localized perforation may demonstrate lack of pneumoperitoneum. Some surgeons recommend surgery for all colonoscopic perforations; however, there does appear to be a role for conservative management in a select group of patients such as those with silent asymptomatic perforations and those with localized peritonitis without signs of sepsis that continue to improve clinically with conservative management. Finally, conservative management works well in those patients with postpolypectomy coagulation syndrome. Surgery is most definitely indicated in the presence of a large perforation demonstrated either colonoscopically or radiographically and in the setting of generalized peritonitis or ongoing sepsis. The presence of concomitant pathology at time of colonoscopic perforation such as a large sessile polyp likely to be a carcinoma, unremitting colitis, or perforation proximal to a nearly obstructing distal colonic lesion may force immediate surgery. Finally, in the patient who deteriorates with conservative management, one should proceed to surgery.