This study of the management of children with fever and urinary tract infection (UTI) was conducted to identify factors associated with initial admission, outpatient treatment, and outpatient treatment failure. A retrospective chart review identified children 3 months to 16 years of age with an emergency department (ED) diagnosis of cystitis, pyelonephritis, or UTI, a positive urine culture, and an ED temperature of >38 degrees C. Sixty-nine patients (90% female) were studied; 19% were admitted initially. Age younger than 2 years was associated with admission (P < .001). Of those initially discharged, 63% received parenteral antibiotics (usually intramuscular ceftriaxone), followed by oral antibiotics; 9% failed outpatient treatment. Outpatient failure was associated with higher initial temperatures (median 40.1 degrees C v 39.2 degrees C, P=.03, Mann-Whitney U) but was unrelated to age, initial white blood cell count, or use of parenteral antibiotics. These results indicate that most children with fever and UTI do not require hospital admission; those with temperatures of > or = 40 degrees C are at increased risk for outpatient failure.