Since its introduction, colonoscopy has played an important role as a diagnostic, therapeutic, and screening tool. In general, colonoscopy is regarded as a safe procedure, but complications may occur. The most dreaded of these complications is colonic perforation. Bacteremia postprocedure may occur, and although it is not uncommon, it rarely results in clinically significant complications. Patients with IBD (inflammatory bowel disease) are a high-risk population for bacteremia, which may leads to bowel wall overstepping by the bacteria. With regard to that, we report a fatal case of gas gangrene complicating colonoscopy polypectomy without bowel perforation in a healthy adult. To the best of our knowledge, only two other cases of retroperitoneal gas gangrene associated with colonoscopy polypectomy without bowel perforation have been described in international literature, but none of which was completed by a molecular biology analysis.