Little attention has been focused on the identification of urinary tract infection (UTI) in young febrile children in the emergency department, despite recent information that suggests both a high prevalence and significant associated morbidity in this population. Most UTIs that lead to scarring or diminished kidney growth occur in children younger than age 4 years, especially babies in the first year of life. Overall, prevalence rates of UTI in febrile infants in the emergency department are approximately 3% to 5%, with higher rates for white girls, uncircumcised boys, and those without another potential source for fever. Prevalence and risk factors are given so that clinicians may identify those febrile children at particularly high or low risk of UTI for selective management. Culturing methods, urine screening tests, and culture interpretation are reviewed and management strategies based on these results are suggested.