Colonoscopy is a safe and standard procedure for diagnosis and therapy of colonic disorders. Iatrogenic colonic perforation during diagnostic colonoscopy, a rare abdominal emergency, has an 0.3~0.8% incidence rate. The choice of treatment for this complication remains controversial. Prompt operative intervention is preferred to minimize morbidity and mortality. However, operative intervention is invasive and needs a long-term recovery period. Conservative treatment is less invasive but can lead to more extensive surgery in case of treatment failure. Very important point on the treatment of iatrogenic perforation of the colon during diagnostic colonoscopy is to avoid the leaking of intestinal contents into the intraperitoneal cavity. We report here a case in which an iatrogenic perforation of the colon during diagnostic colonoscopy was successfully treated by endoscopic clip therapy.