A total of 801 samples included 179 clinical samples and 622 animal samples were collected from Baghdad province. All samples were cultured on blood agar and MacConkey agar plates to isolate Proteus mirabilis bacteria. Results showed that rate isolates of P. mirabilis from clinical and animal samples were 25.89% (51/179) and 5.95% (37/622) respectively. Antibiotic susceptibility test showed that lowest resistance rates for clinical P. mirabilis isolates were 3.9% for ciprofloxacin, 7.8% for norfloxacin, 9.8% for imipenem, 13.7% for levofloxacin and 15.7% for cefotaxime, and highest resistance rates were 82.4% for cefepime, 78.4% for piperacillin, 56.9% for ceftazidime and 54.9% for cefoxitin. In regards to animal isolates, they were 100% sensitive to cefoxitin and 100% resistance to piperacillin. Their resistance rates were 2.7% to amikacin, 5.4% to ciprofloxacin and 8.1% to cefepime, imipenem and levofloxacin. The results revealed that all P. mirabilis isolates were 100% multidrug resistance for 2-8 antibiotics. Extended -lactamases produced were detected in 52.94% of clinical P. mirabilis isolates and in 48.65% of animal isolates.