Urinary tract infection (UTI) is the most common infectious disease of the elderly and is especially prevalent in debilitated, institutionalized older individuals. Unlike UTI in younger women, which tends to be related to frequency of sexual intercourse and is uncomplicated, in the elderly it is more difficult to treat and its pathogenesis is related to abnormal bladder function, bladder outlet obstruction, vaginal and urethral atrophy, use of long‐term indwelling catheters, and puddling related to bed rest. The spectrum of organisms causing infection relates to the ecology of the patients' environments; those residing in nursing homes and especially with permanent indwelling catheters tend to have a greater variety of pathogenic organisms, many of which may be relatively antibiotic resistant. Short‐course antibiotic therapy is less effective in older patients, and relapse or recurrence is more common regardless of the duration of treatment. Asymptomatic bacteriuria is common in older patients with abnormal bladder function. The clinical significance of asymptomatic bacteriuria generally is minor, and treatment is not benefic