AIM:To determine the incidence of colonoscopic perforation (CP), and evaluate clinical findings, management and outcomes of patients with CP from the World Gastroenterology Organization (WGO) Endoscopy Training Center in Thailand. METHODS: All colonoscopies and sigmoidoscopies performed between 1999 and 2007 in the Endoscopic unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok were reviewed. Incidence of CP, patients' characteristics, endoscopic information, intraoperative findings, management and outcomes were analyzed. RESULTS: A total of 17 357 endoscopic procedures of the colon (13 699 colonoscopies and 3658 flexible sigmoidoscopies) were performed in Siriraj hospital over a 9-year period. Fifteen patients (0.09%) had CP: 14 from colonoscopy and 1 from sigmoidoscopy. The most common site of perforation was in the sigmoid colon (80%), followed by the transverse colon (13%). Perforations were caused by direct trauma from either the shaft or the tip of the endoscope (n = 12, 80%) and endoscopic polypectomy (n = 3, 20%). All patients with CP underwent surgical management: primary repair (27%) and bowel resection (73%). The mortality rate was 13% and postoperative complication rate was 53%. CONCLUSION: CP is a rare but serious complication following colonoscopy and sigmoidoscopy, with high rates of morbidity and mortality. Incidence of CP was 0.09%. Surgery is still the mainstay of CP management.