We propose guidelines for the management of perforation of the colon at colonoscopy based upon a comprehensive literature review. Conservative management is advocated for silent perforations and in patients with mild or localized symptoms and signs diagnosed within 4-8 h of injury. Perforations diagnosed late may be managed by nonoperative methods, if the infection is confined as determined clinically or by imaging techniques. A suspected large perforation, generalized peritonitis, or failure to improve on conservative management will mandate surgical exploration. In an intermediate group of patients, decisions regarding management will depend on crucial information regarding the circumstances surrounding the procedure. These include the endoscopist's assessment of the size, mechanism, and timing of the perforation, the adequacy of bowel preparation, delay time to diagnosis, overall condition of the patient, and the presence or absence of associated colonic pathology. Antibiotic therapy should be given to all patients immediately upon diagnosis. Single-agent therapy with cefoxitin can be used in the immunocompetent patient. Under other circumstances, combination antibiotic treatment is indicated.