The aim of this study is to determine the antimicrobial resistances of Enterobacter species isolated from clinical specimens of outpatients and hospitalized patients at our hospital between April 2002 and February 2003. Of the total 120 Enterobacter strains, 78 has been isolated from hospitalized patients and 42 from outpatients. Resistance rates for antibiotics of isolates was found as follows; %94.9, %78.6 for ampicillin; %85.9, %83.3 for amoxicillin-clavulanic acid; %93.6, %83.3 for cefazolin/cephalothin; %57.7, %42.6 for cefuroxime; %52.7, %19 for ceftazidime; %53.8, %30.6 for ceftriaxone; %51.3, %28.6 for cefotaxime; %65.4, %42.6 for piperacillin; %7.7, %2.4 for amikacin; %25.6, %4.8 for gentamicin; %43.6, %9.5 for tobramycin; %11.5, %4.8 for ciprofloxacin; %10.2, %4.8 for imipenem; %56.4, %33.3 for aztreonam; %50, %35.7 for tetracycline %32.1, %21.4. for trimethoprim-sulfamethoxazol in hospitalized and outpatients, respectively.