Purpose:There is a close correlation between favour of initial antimicrobial therapy and mortality of infection in febrile neutropenic patients. Material and Methods:Isolated microorganizms from febrile neutropenic patients with hematologic malignancy and their antimicrobial susceptibility was evaluated by retrospective. We evaluated the results of blood, sputum, urine, wound and catheter tip cultures of these patients. Results:Among 206 isolates, in 134 episodes, from blood and other cultures of 86 of 176 febrile neutropenic patients, gram-negative bacteria was prevalent (74.2%). Among the gram-positives coagulase-negative staphylococci (CNS) were the predominant bacteria (39.6%). Bacteremia in 77(37.7%) patients and polymicrobial isolation in 13 (15.1%) patients was obtained. Escherichia coli and Klebsiella spp. were the most common species among gram-negative bacteria. E. coli has been the highest rate of antibacteriel resistance against ciprofloxacin (68%), followed by piperaciilin-tazobactam (44,7%) and cefepime (38.1%).Furthermore, increasing incidence of carbapenem resistant strains and that strains are nosocomial multidrug resistant gram negative bacteries are remarkable. Although the rate of gram positive microorganisms is less than gram negatives, the rate of antimicrobial resistance is increasing. Conclusion:It is most suitable and rationalist approach that ampiric treatment of febrile neutropenic patients is manage according to results of local epidemiolgic data, frequency and susceptibility pattern of isolated microorganisms.