Background: Uropathogenic Escherichiacoli (UPEC) are among the most common agents of urinary tract infection (UTI) worldwide. UPEC resistance to commonly used antibiotics represents a major health problem all over the world. Antimicrobial susceptibility testing provides information that allows physicians to select the most appropriate antimicrobial agents for treating a specific infection. This study aimed to assess the Antimicrobial susceptibility pattern of Escherichia coli causing urinary tract infections in Tehran, Iran.Methods: A total of 103 UPEC isolates were collected from in and out-patients attending various hospitals in Tehran between March 2013 and February 2014. The samples were cultured on LB Broth media and the bacterial isolates were tested against antibiotics Trimethoprim-sulfamethoxazole, Nitrofurantoin, Nalidixic acid, Gentamycin, Cephalexin, Norfloxacin, Ceftazidime, Amikacin, Ofloxacin, Ceftriaxone and Ticarcillin using Kirby Bauer disk diffusion method according to the CLSI.Results: Up to 65% of the isolates were resistant to Trimethoprim- sulfamethoxazole and about 90% of the isolates were susceptible to Ticarcillin, Amikacin and Ofloxacin; and 80% of the isolates were susceptible to Cephalexin, Nalidixic acid, Gentamycin, Norfloxacin, Ceftazidime, Ceftriaxone and Nitrofurantoin.Conclusion: The obtained results suggest that antibiotic selection for empirical treatment should be based on individual drug-sensitive test results. There is also an urgent need to develop a new combination of chemotherapeutic agents and awareness on antibiotic use should only be issued when prescribed by physicians for the effective UTI management in hospitals.