Bacteriuria is much more common among elderly than among younger populations, and is most often asymptomatic. Asymptomatic bacteriuria in the elderly is a benign condition in the vast majority of cases and does not require therapy. When symptomatic lower UTI occurs, short-course (3-day) therapy with any of several agents is indicated, and is usually effective. Women with frequently recurrent symptomatic UTI may benefit from estrogen therapy. Fourteen days of therapy is indicated in patients with upper UTI. The typical signs and symptoms of pyelonephritis may be altered or absent in elderly patients.