Urinary tract infection (UTI) accounts for 15.5% of hospitalizations by infectious disease in over age of 65, second only to pneumonia, and they are responsible for 6.2% of infectious disease related deaths. UTI and asymptomatic bacteriuria (ASB) are very common in elderly. Distinguishing symptomatic urinary tract infection from asymptomatic bacteriuria is often difficult especially in old people living in long-term care facilities due to lack of specific symptoms. As the population is getting older, UTIs and ASB in elderly adults represent a significant health care burden. However, there is no exact data on morbidity of UTIs in elderly persons in Korea. This article reviews the prevalence of ASB and the incidence of symptomatic UTIs.