To identify the prevalence of asymptomatic bacteriuria in the elderly population and to examine associated risk factors, complications and natural history, and whether treatment improves prognosis. A literature search of MEDLINE, PubMed and the Cochrane Library was undertaken of studies published from 1980 to 2009. A total of 70 articles were identified. Emphasis was given to randomised controlled trials, review articles and more recent publications. Asymptomatic bacteriuria is common in the elderly, especially among institutionalised or hospitalised patients. Risk factors include cognitive impairment, diabetes mellitus, structural urinary tract abnormalities and indwelling catheters. Antimicrobial therapy does not result in improved survival or genitourinary morbidity and may potentially cause avoidable side effects and the emergence of resistant organisms. Bacteriuria is common in functionally impaired elderly patients. In the absence of symptoms or signs of infection, routine dipstick screening and subsequent antimicrobial therapy is not recommended.