Acinetobacter species are increasingly identified as opportunistic pathogens and becoming more resistant to antimicrobials. In this study, we investigated antimicrobial susceptibilities of Acinetobacter strains isolated from patients in different departments in the hospital of Cerrahpasa Faculty of Medicine, University of Istanbul. The susceptibility patterns of the strains were assessed by disc diffusion method. Sixty-five A. baumannii, 32 A. twoffi and 5 A. junii strains were recovered from various clinical specimens. The resistance of strains was found to be 80-88 % to mezlocilline, cefotaxime, ceftriaxone, cefoperazone and gentamicin, 40-50 % to ofloxacin and ciprofloxacin, 20-38 % to imipenem and 0-25 % to sulbactam-cefoperazone. Our results reveal that Acinetobacter species have developed multi-drug resistance and sulbactam-cefoperazone, imipenem, amikacin and ciprofloxacin are agents of choice in the empirical therapy.