We report a case of fatal necrotizing soft tissue infection (NSTI) due to Clostridium perfringens (CP) in a neutropenic patient with diabetes mellitus. As in many cases, by the time a diagnosis was made, the condition had rapidly progressed to its late stages, resulting in a fatal outcome. The emergency physician should be aware of NSTI as a complication when patients present with pain out of proportion to physical findings and/or signs of soft tissue compromise. Negative prognostic factors for survival are diabetes mellitus, immunosuppression, age, and toxic shock syndrome. A bedside ultrasound scan allows for rapid evaluation in time-sensitive critically ill patients and can promote prompt treatment without the need to delay for further imaging studies.