Infection in chemotherapy-induced neutropenia (neutrophils <500/mm3) is the main cause of death during the treatment of acute leukemia. Antibiotic prophylaxis is a controversial issue to prevent or delay this infection. This study assessed the efficacy of prophylaxis with oral levofloxacin in chemotherapy-induced febrile neutropenic patients. Eighty patients of acute leukemia was randomly assigned to had levofoxacin (500 mg/daily) or placebo from the starting of chemotherapy. Out of 80 patients 53 developed neutropenia and fever. The number of patients with fever (78% vs. 68%), isolation of the pathogenic bacteria (30.43% vs. 16%) was higher and mean starting day of the fever (11.1 vs. 13.2) was shorter in the placebo group than the levofloxacin group. Levofloxacin reduced the bacterial infections and delays the onset of fever in chemotherapy-induced neutropenia especially in short duration (<7 days).