Abstract: The detection of β-lactam-resistant A. cinetobacter baumannii in Diyala city and their resistance genetic mechanisms was undertaken. We studied the extended-spectrum beta-lactamase genes, particularly the PER-1 gene, among β-lactam-resistant A. baumannii isolates from patients from patients suffering from urinary tract infections in teaching Baquba hospital and Al-Betul hospital in Diyala city. From April to October (2015), 250 urine samples were collected. And the results of bacterial culture on media of MacConkey agar, blood agar and biochemical tests and confirm the diagnosis using Api 20 E system and Vitek 2 compact system showed that 8 isolates are belonging to bacteria of Acinetobacte baumannii. Fresh subculture samples were tested for antimicrobial susceptibility against (11) antibiotics using disk diffusion method, the results revealed that all isolates were variable resistance to ampicillin, aztreonam, ceftazidium, cefotaxime, cefepime, ciprofloxacin, piperacillin, meropenem, nalidixic acid and amikacin (62.5, 50, 75, 75, 50, 50, 75, 37.5, 50 and 25%), respectively. Whearase all isolates were sensitive to antibiotic imipenem. Total genomic DNA was extracted from each isolate and further used for Polymerase Chain Reaction (PCR). The results of detection of β-lactam resistance gene by molcular technique PCR revealed that of these 8 isolates, 6 were found to harboring PER-1 gene.