The association between Clostridium septicum sepsis in patients with malignant disease has been frequently documented. A presentation with fever, neutropenia, vomiting, and an acute abdomen is characteristic of this anaerobic infection which has been uniformly fatal in children with acute leukemia. We report the unusual course and the successful treatment of an adolescent with an abdominal Burkitt's lymphoma with leukemic transformation and clostridium septicum sepsis and cellulitis.