Purpose: Worldwide data shows that there is an increasing resistance among urinary tract pathogens to the first-line antimicrobial agents used in domestic areas. The objective of this study was to obtain data on the susceptibility patterns of the pathogens responsible for acute uncomplicated cystitis to currently used antimicrobial agents. Materials and Methods: This study was carried out with the participation of fifteen hospitals in South Korea. A total of 239 isolates were obtained from female outpatients with acute uncomplicated cystitis. The antimicrobial susceptibilities to ampicillin, ampicillin/ sulbactam, ciprofloxacin, gentamicin, trimethoprim/sulfamethoxazole (TMP/SMX) and tobramycin were determined by Vitek？ antimicrobial susceptibility test systems.