Background and Objectives: Acinetobacter species are responsible for a wide range of clinical complications in hospitalized patients. Antimicrobial treatment of clinical strains of Acinetobacter baumannii may be compromised due to multiple-drug resistance to -lactams. Aim of this study was to determine antibiotic resistance patterns and frequency of PER and VEB genes in A. baumannii isolates from hospitalized patients.Methods: In this cross-sectional study, 100 clinical strains of A. baumannii were isolated from patients hospitalized in Qom (Iran) using specific culture media and biochemical tests. The disk diffusion method was performed to determine resistance to some antibiotics. Minimum inhibitory concentration (MIC) for cefepime and ceftazidime was evaluated. Identification of ESBL-producing strains and presence of the PER and VEB genes were determined by combined disk test and polymerase chain reaction, respectively.Results: The isolates were highly resistant against cefixime, ceftriaxone and cefepime. Lowest level of resistance was against polymyxin B. In addition, 70% of the isolates were multi-drug resistant. MIC<128 µg/ml to ceftazidime and cefepime was observed in 84% and 91% of the strains, respectively. Moreover, 21% of the strains were ESBL-positive and frequency of the PER and VEB genes was 47% and 32%, respectively.Conclusion: Majority of A. baumannii isolates are highly resistant to the tested antibiotics. Due to presence of the PER and VEB genes in the isolated strains, there is the possibility of resistance spread to other bacteria. Therefore, it is recommended to modify the consumption pattern for antibiotics and pay more attention to standards of nosocomial infection control.