The choice of therapy in urinary tract infections depends on the infection site, complications, previous history, and recrudescence. Acute uncomplicated urinary tract infections which do not respond to general measures as increased fluid intake will be cured with antibiotics for 3 days. If the compliance of the patient is sufficient a single shot therapy may be applied. Infections of the upper urinary tract with typical signs such as fever, nausea and increase of the so-called acute phase proteins have to be treated with antibiotics for 7 to 14 days. When treating the first episode of urinary tract infection the choice of antibiotics is unimportant. Trimethoprim and quinolones are standard. In recurrent infections urine cultures and susceptibility testing are mandatory. Patients with recurrent urinary tract infections should receive a long-term suppressive therapy with low-dose trimethoprim or a quinolone. Patients with urinary catheters must not receive any long-term therapy.