Acinetobacter baumannii an opportunistic pathogen and identified multidrug-resistant bacteria poses a significant global medical threat due to their ability to survive in a hospital environment cause nosocomial infections and develop various resistance mechanisms as an acquisition of multiple genes to resist antibiotics, especially carbapenem, it can hydrolyze this antibiotic because it has class D β-lactamases (oxacillinases). Our study focused on determining the existence of the blaOxa23 gene in strains of Acinetobacter baumannii resistant to many antibiotics isolated from various clinical samples in Mosul City, IRAQ, Three hundred samples (environmental and clinical) were collected from hospitals and the Burns Center in Mosul City, Iraq, During September 21, 2023, and January 1, 2024.The samples were cultured on MacConkey medium as a differentiation medium for Gram-negative bacteria, and biochemical tests, IMVIC test, and molecular diagnosis were performed.  Out of 200 clinical sample and 100 environmental sample 24 isolates of Acinetobacter baumannii were detected, DNA was extracted, and PCR was applied to discover the genes of blaOxa23 . The outcomes revealed possesses the blaOxa23 gene in all selected bacterial strains resulting in a product size of 501 base pairs, our results indicate a high incidence of the blaOxa23-like gene, serving as a resistance marker to  all  ten antibiotics(Amikacin, Azithromycin, Ceftazidime, Ceftriaxone, Ciprofloxacin, Gentamicin, Imipenem, meropenem, Levofloxacin and piperacillin _tazobactam) among Acinetobacter baumannii in the study region.