Acute cystitis is one of the commonest medical problems encountered by primary care physicians. It affects more women than men (8:1), but the incidence among men is increasing. Uncomplicated cystitis by definition occurs in healthy patients with a normal urinary tract, whereas complicated cystitis implies a predisposing or underlying condition. A narrow range of aetiological agents is responsible for most uncomplicated cystitis in women (Escherichia coli in 80% of cases). Recently, however, pathogens usually associated with sexually transmitted disease have been implicated. In women with typical symptoms of acute uncomplicated cystitis, an abbreviated laboratory work-up followed by empirical therapy is recommended. Single-dose and 3 day regimens of co-trimoxazole and the quinolones are as effective as longer regimens and have a higher eradication rate than other commonly used antimicrobials. Relapse rates are slightly higher with single-dose therapy. With this success rate plus the reduced cost and improved patient compliance, these regimens have replaced traditional 5 to 14 day courses of treatment. With increasing resistance of the common urinary pathogens to amoxycillin and, now, co-trimoxazole, the quinolones are a logical choice for empirical therapy of uncomplicated urinary tract infections.