Gas gangrene is a rare, life-threatening deep skin infection typically related to contaminated wounds, although it may occur without injury. Non-traumatic gas gangrene due to Clostridium spp. is most commonly caused by Clostridium septicum. We present the case of a patient who expired of atraumatic gas gangrene due to Clostridium septicum. C. septicum infection is rapidly progressive and is associated with colorectal cancer and diabetes mellitus. We emphasize that it is important to diagnose and treat patients with gas gangrene by early recognition and aggressive debridement.