The objective of this study was to obtain data on the susceptibility of pathogens responsible for acute uncomplicated cystitis in South Korea to currently used antimicrobial agents. A total of 239 isolates were obtained from female outpatients with acute uncomplicated cystitis. The most prevalent causative organism was Escherichia coli (79.9%), followed by coagulase-negative staphylococci (CNS) (4.2%) and Enterobacteriaceae (8.2%). The mean rates of susceptibility to commonly prescribed drugs are ampicillin 35.5%, cefazolin 89.1%, ciprofloxacin 85.7%, and trimethoprim/sulphamethoxazole (TMP/SMX) 62.1%. Regionally, resistance to TMP/SMX among E. coli now exceeds 30% in all regions. The high prevalence of resistance among uropathogens requires on going surveillance to ensure the provision of effective empirical therapy for acute uncomplicated cystitis.