From 1987 to 1991, we performed intraoperative colonoscopy on 66 patients as a result of the following indications: the air leakage test (53%), detection of a previous malignant polypectomy site (20%), inability to complete preoperative colonoscopy (17%), detection of the source of intestinal bleeding (4%), and detection of impalpable colonic lesions (4%). Intraoperative colonoscopy was successful in 61/66 patients and provided information that altered the planned operation in 10 of 61 completely examined patients. The air leakage test proved useful in detecting subclinical anastomotic leaks. The indications for intraoperative colonoscopy have been expanded, and this procedure is often useful when one is attempting to decide on the appropriate surgical strategy for patients.