To assess the clinical efficacy of oral antibiotic administration for the treatment of lower urinary tract infection (UTI), 102 female patients were given gatifloxacin (200 mg once daily for 3 days). Five to nine days after treatment, drug safety and clinical efficacy were assessed by evaluation of urinalysis and symptoms. Further, the patients were asked to report by mail whether they had persistent or recurrent symptoms at 4-6 weeks after treatment. The overall clinical cure rate was 93.1% (95/102). Of 94 patients with susceptible pathogens and 8 with resistant pathogens, 89 (94.7%) and 6 (75.0%), respectively, were judged as clinically cured. Four to 6 weeks after treatment, 57 (55.9%) of the 102 patients reported their micturition status by mail, and 6 (10.5%) of them claimed that they had some symptoms. The outcomes of this study suggest that a therapeutic regimen such as administration of fluoroquinolones once daily for 3 days can be recommended for the treatment of uncomplicated cystitis.