Background: Clostridium septicum is a gram-positive, anaerobic, spore-forming bacilli found in the gastrointestinal tract. It rarely causes spontaneous infections that are associated with high mortality. Association of Clostridium infection with colorectal malignancies or immunosuppression have been reported previously, tumors of the ascending colon are described in most cases. The anaerobic glycolysis of the tumor produces an acidic, hypoxic environment favoring mucosal ulceration and bowel into bloodstream translocation, leading to fulminant sepsis, infected liver metastases, and hollow viscous perforation presenting as pneumoperitoneum. Case Presentation: We report a case of a 61-year-old male with type 2 diabetes mellitus and chronic lymphocytic leukemia who presented with five-day generalized abdominal pain and fever. His symptoms were caused by colon cancer with liver metastases infected with Clostridium septicum. The clinical outcome and management of the case is reported. Conclusion: In patients with hematologic or colorectal cancer and gas-forming liver abscesses, the possibility of Clostridium septicum infection and metastatic cancers should be considered. The aim of this case is to stress the importance of maintaining a high suspicion of Clostridium septicum infection in patients with underlying colonic malignancy.