The resistance of Acinetobacter baumannii to most antibiotics is increasing. The presence of metallo-beta-lactamase and carbapenemase enzymes has led to the resistance of these bacteria to carbapenems as one of the major classes of broad-spectrum antibiotics and has raised concerns in human societies. This research evaluated the presence of blaOXA-51, blaOXA-58 and blaOXA-23 genes in A. baumannii strains during a 12 months period. One hundred strains were isolated from the patients hospitalized in ICU of Ali Asghar and Shahid Rajaee trauma hospitals in Shiraz. Bacterial identity was determined by biochemical tests and antibiotic resistance was determined by disk diffusion method. The isolated strains were then evaluated in terms of carrying blaOXA-23, blaOXA-51 and blaOXA-58 genes, using the multiplex PCR method. The results showed that A. baumannii was resistant to carbapenems but most strains were susceptible to tigecyclin and colistin. The majority of strains carried the blaOXA-23 and blaOXA-51 genes, but very few carried the bla OXA-58 gene. The results revealed that the antibiotic resistance of A. baumannii is increasing, which causes a more outbreak of this organism.