This retrospective study of 44 attacks of fever during the agranulocytic stage of treatment of acute myeloblastic leukemia in adults, sought the cause of the fever, the efficacy of antibiotic associations and the efficacy of white cell transfusions. In 28 cases, the fever was associated with bacterial or mycotic infection, proved in 19 cases. Appropriate antibiotic therapy alone was able to cure the fever, whereas white cell transfusion did not seem of any use. In the 16 other cases, the fever appeared alone. Antibiotic associations were ineffective, whereas the fever was cured by white cell transfusions or cure of the agranulocytosis.