The present investigation aimed to compare the in vitro antimicrobial activity of prulifloxacin to that of levofloxacin and ciprofloxacin against recently urinary pathogens. From our large bacterial collection, 978 non-duplicated clinical isolates, derived from patients urinary infections, maintained with minimal sub-culture deep frozen at -70 degrees C in a matrix of Brain Heart Infusion broth +20 % glycerol were tested to determine MICs of prulifloxacin, levolfoxacin and ciprofloxacin by means of broth microdilution technique. For Gram negartive bacteria, no significant diffrences was observed between all three antibiotics. Enterobacteria showed a resistance rate ranging between 6% (Enterobacter spp) and approximately 20% (Escherichia coli). Antibiotic resistance of Pseudomas spp was higher (30.3%). For Gram positive, all methicillin-susceptible Stalphylococcus aureus strains were sensitive whereas 30% of methicillin-resistant and enterococci were resistant to all three antibiotics. Purification exerts its antibacterial activity at lower concentrations than ciprofloxacin and levofloxacin. The in vitro activity of prulifloxacin against urinary pathogens and its high and prolonged urinary concentration following a single oral dose, suggest that for treatment of urinary prulifloxacin is an alternative to other flouroquinolones for treatment of urinary tract infections.