Tetanus is a neurologic disorder caused by a tetanospasmin released from Clostridium tetani and usually occurs as a result of a dirty open wound or abrasion. Post traumatic tetanus is a life threatening disease and has a mortality rate of 15~39%. Because of a nationwide active immunization program, tetanus is a rare disease in Korea. Thus, many physicians have little experience with its diagnosis and management, and misdiagnosis and therapeutic delay may have catastrophic consequences. We report a case of tetanus that developed in a patient who had been diagnosed with a traumatic rectal rupture.