Objective: Resistant gram-negative bacterial infections that cause hospital-acquired infections are becoming increasingly problematic. Due to the carbapenem resistance that develops in these bacteria, treatment options are restricted, the duration of hospitalization is longer and the mortality increases. This requires the addition of options such as tigecycline and colistin to treatment. The aim of this study is to determine the susceptibility of gram-negative bacteria isolated from various clinical specimens in a private hospital and to determine the appropriate antibiotics in patients. Methods: In our study, 1109 bacterial strains which were produced in various clinical samples were examined in Private Kadıköy Florence Nightingale Hospital between February 2018 and February 2019. Bacteria in the samples are defined in accordance with the recommendations of the manufacturer of the conventional methods, Vitec 2 (Biomeriux, France) automated system. Sensitivity tests were performed by Vitec 2 (Biomeriux, France) automated system and interpreted according to EUCAST criteria. The data were retrospectively evaluated. Results: The most common samples of the study were blood and urine. The most effective antibiotics for Escherichia coli (50.9%), based on the type and sensibility of the identified bacterides, were meropenem (99.6%), imipenem (99.2%), fosfomycin (98.5%), amikacin (96.7%), colistin (98.3%), tigecycline (96.7%). Klebsiella spp. the most effective antibiotics were amikacin (95.2%) and meropenem (92.6%), imipenem (92%), colistin (95.8%) and tigecycline (96.7%). The most effective antibiotics for Proteus spp. were meropenem (95.7%), piperacillin/tazobactam (95.7%) and phosphomycin (91.2%). The sensitivity of tigecycline was found to be 15.4%. The most effective antibiotics for Enterobacter spp. were imipenem (100%), amikacin (100%) and ciprofloxacin (93.1%). The most effective antibiotics for Pseudomonas aeruginosa were amikacin (80.3%), ciprofloxacin (77.4%), colistin (94.7%) was determined. Conclusion: Each center is supposed to know the distribution of gram-negative bacteria, resistance patterns and changes in years, isolated from their own clinical samples. In order to prevent hospital infections and antibiotics, there must be an antibiotic management plan under the responsibility of the infection control committee that is applied by the hospital.