Fiberoptic colonoscopy provides superior diagnostic and therapeutic capabilities in the treatment of lower gastrointestinal disease processes. A well-recognized, but uncommon, complication during the procedure is perforation. The purpose of this study was to determine the incidence of colonoscopic perforation, define risk factors, assess the management of these complications, and evaluate outcomes. From January 1997 through December 2003, 43,609 colonoscopies were performed in our medical center. There were 14 (0.032%) perforations (1 in 3115 procedures); 7 from diagnostic and 7 from therapeutic procedures. General surgeons performed 1243 procedures (2.9%), and their rate of perforation was 0.080 per cent compared with 0.031 per cent for gastroenterologists during the same period. Half of the perforations occurred in the rectosigmoid, and the most common mechanism was mechanical (n = 6). Perforation was identified immediately during endoscopy in 50 per cent of the patients. Thirteen of 14 perforations were treated within 24 hours; 1 was delayed 48 hours. Initial surgical management was undertaken in 11/14 patients. Initial nonoperative treatment was attempted in three and was successful in only one patient. The mean length of stay following perforation was 11.2 days (range, 4-36 days). Three patients (21.4%) had 7 postoperative complications. Colonoscopic perforations are uncommon but can be recognized early and managed surgically with acceptable morbidity and postoperative length of stay.