The aim of this study was to carry out a small-scale bacteriological comparison between a standard therapy with norfloxacin 400 mg twice daily, and fosfomycin trometamol (3 g) in single dose in uncomplicated urinary tract infections (UTI) in women. Only patients with UTI with cultures showing a bacterial count of 10(5) or more bacteria/ml were included in the study (n = 32; ages 16-75 years). After one week sterile cultures were obtained in 14 of 16 cases in the fosfomycin trometamol group, and in 14 of 16 cases in the norfloxacin group. After one month eradication was confirmed in 13 of 16 patients in the fosfomycin trometamol group, and in nine of 16 patients in the norfloxacin group. Recurrence was seen in one case in the fosfomycin trometamol group, and in five cases in the norfloxacin group. The reinfection and persistence rates were identical (1/16) in both groups. The main clinical symptoms disappeared very rapidly after initiating treatment, and the correlation with the bacteriological data after one week was excellent. Both drugs were well tolerated and the compliance for fosfomycin trometamol was 100%.