This retrospective study was done to determine the most common microorganisms and their antibiotic susceptibilities in urine samples from the patients with urinary tract infections. In this study, 511 urine cultures with the evidence of infection, obtained from two different microbiology laboratories, were included. Escherichia coli was found to be the most common isolated microorganism. Susceptibility was found to be 99.4 % to imipenem, 83.3 % to ceftriaxone, 82.5 % to gentamicin, 74.9 % to ciprofloxacin, 44.6 % to sulbactam/ampicillin, 28.4 % to trimetoprim-sulfamethoxazole, 16.6 % to ampicillin in isolated microorganisms. These results showed that ampicillin and trimetoprim-sulfamethoxazole are inappropriate for empirical treatment of urinary tract infections.