Urinary tract infections (UTIs) are one of the most common reasons people seek medical attention. There are > 50% of women who will have at least one UTI during their lifetime and most of these will require a physician visit and antibiotic treatment. The high prevalence continues to the in-patient setting where genitourinary infections are the most common nosocomial infection. The efficient diagnosis and effective treatment of UTIs is a major healthcare concern. Factors such as economic efficiency and emerging resistance are increasingly becoming more important considerations in providing patient care. In out-patient uncomplicated UTIs, Escherichia coli has been implicated in < or = 75-90% of cases. Although the prevalence in the in-patient setting decreases, E. coli is still the most common bacteria identified and present in 21-54% of urinary isolates. Trimethoprim-sulfamethoxazole has been the preferred first-line agent for uncomplicated out-patient UTIs where local resistance is < 10 - 20%. In recent years, resistance has superseded this threshold in most regions of the US and Europe. In these areas with increased resistance, fluoroquinolones have become a common first-line agent. Ciprofloxacin has been one of the most widely used fluoroquinolones and has a well-known safety profile, as well as excellent activity against most of the common uropathogens. Ciprofloxacin extended release (ER) is a recently released once-daily formulation that has been increasingly used with good clinical success. The pharmacokinetic and pharmacodynamic parameters of ciprofloxacin ER are shown to be at least equal to twice-daily ciprofloxacin and may even confer superiority as ciprofloxacin ER achieves a higher maximum serum concentration. This is supported by clinical studies, which have shown at least as effective clinical cure and bacteriological eradication rates. These studies have also demonstrated similar tolerability and side-effect profiles. Ciprofloxacin ER combines traditional ciprofloxacin's proven track record of efficacy and safety with favourable pharmacokinetics and convenient once-daily dosing. Increased patient compliance is associated with decreased treatment failures and can help slow the development of antimicrobial resistance. Economic considerations are also increasingly important and providing convenient and effective treatment leading to high clinical success decreases overall costs.