A 61-year-old man developed a pyrescia accompanied by a massive intravascular hemolysis after abdominal surgery (Whipple's operation) of a pancreatic adenocarcinoma. Abdominal ultrasound and the abdominal CT-scan showed marked aerobilia and multiple liver abscesses. Laboratory tests demonstrated the presence of the Thomsen-Friedenreich cryptantigen (TCA) on the membranes of the patient's erythrocytes. The enzymatic cleavage of N-acetyl-neuraminic acid usually covering the TCA may lead to a life threatening intravascular hemolysis. Since Clostridial bacteriae typically synthesize neuraminidase, the presumptive diagnosis of Clostridial sepsis complicated by massive hemolysis was made. Immediate antibiotic therapy including penicillin G and metronidazole stopped hemolysis within a few hours and the patient servived. On the following day, microbiological examination identifiedClostridium perfringens in the patient's blood cultures. Clostrial sepsis should be suspected in patients with underlying infections and/or malignant diseases, particularly of the gastrointestinal or genitourinary tract, who present with septic shock and acute intravascular hemolysis. Whereas microbiological specification of the organism is time consuming, the relatively simple agglutination test with anti-TCA peanut lectin can provide a rapid presumptive diagnosis. The immediate onset of an appropriate antimicrobial therapy is of central importance and might be life-saving.