Cefixime (CFIX, Cefspan), a new oral cephem, was used in the treatment of urinary tract infections, and was evaluated for its therapeutic effectiveness and safety at the Department of Urology, Osaka University Hospital and 16 affiliated hospitals. A total of 238 patients were administered daily doses of 200 or 400 mg. Clinical efficacy was assessed on 92 female patients with acute uncomplicated cystitis and 42 patients with complicated UTI according to the Criteria for Clinical Evaluation of Antimicrobial Agents in UTI (3rd ed.) recommended by the Japan UTI Committee, to which we added our own minimum modification. Clinical efficacy was evaluated as excellent in 57 of the acute uncomplicated cystitis cases, moderate in 33 and poor in 2, with an overall clinical effectiveness rate of 98%. Clinical efficacy was evaluated as excellent in 12 of the complicated UTI cases moderate in 12 and poor in 18, with an overall clinical effectiveness rate of 57%. In one case of uncomplicated pyelonephritis, CFIX showed an excellent efficacy. Of the total of 102 bacterial strains isolated from uncomplicated UTIs, 95 (93%) were eradicated by CFIX, while 36 (72%) eradicated in 50 strains isolated from complicated UTIs. Subjective adverse reactions were seen in 4 cases (1.7%) of the 236 patients, as generalized pruritus and upper gastrointestinal discomforts. Abnormal laboratory findings were recorded in 6 out of 141 cases. They were increases in serum GPT, GOT, alkaline phosphatases, total bilirubin, as well as increases in peripheral leukocytes. These adverse symptoms and abnormal laboratory findings disappeared after the termination of CFIX administration. CFIX might therefore be considered as a clinically useful oral antibiotic in the treatment of UTI.