In this study we evaluated the efficacy of enoxacin in treating complicated urinary tract infections (UTI). We isolated 21 bacterial strains from 20 enrolled patients and all the strains showed "in vitro" susceptibility to enoxacin. The most represented bacterial strain was E. coli (47.7%). After 48 hs and after 30 days from the end of the treatment, we observed clinical and bacteriological recovery in 65% and 55% of the patients, respectively. However, 6 out of the 20 patients (30%) interrupted the treatment due to mild-severe side effects. In conclusion, enoxacin showed a good antibacterial activity, but it could be necessary to lower daily dosage and to extend the treating period to prevent side effects.