Haemolytic anaemia caused by Clostridium perfringens is a rare complication in patients with neoplastic diseases. According to the literature, our patient seems to be the first patient with underlying malignancy (multiple myeloma) who has survived C. perfringens septicaemia complicated with acute haemolysis and acute anuria. It is concluded that treatment with penicillin should be considered in case of acute haemolytic anaemia, if the patient is febrile and no other obvious cause of the haemolytic condition can be found.