Clostridium tertium septicemia is a rare condition that predominantly occurs in neutropenic patients with concomitant abdominal disease. We report the fatal case of a nonneutropenic, 51-year-old patient with mechanical ileus and post-operative C. tertium septicemia, resulting in widespread pathology with multi-organ failure. As C. tertium is aerotolerant, often gram-variable and mostly resistant to broad-spectrum cephalosporins, differentiation is difficult and empirical therapeutic strategies may fail.