Urinary tract infection is a common medical diagnosis. The decision to treat is based on presenting signs and symptoms, bacterial colony counts in urine, and the nature of the infection. Escherichia coli is the single most frequent cause of urinary tract infections, although, depending on the clinical presentation and presence of risk factors, other pathogens may also be implicated. A variety of antimicrobial agents are available for the treatment of urinary tract infections. Fluoroquinolones are useful because these agents have broad-spectrum antimicrobial activity, resistance to these agents is minimal, and they achieve high concentrations in the urinary tract, have long elimination half-lives in urine, and are well tolerated.