Sixty-nine children younger than 13 years of age with urinary tract infection were evaluated to identify risk factors for treatable urologic problems; i.e. those requiring surgery or prolonged antibiotic prophylaxis. All children had a renal ultrasound, intravenous pyelogram and voiding cystogram performed 4 to 6 weeks after the infection. Eleven children with treatable problems were identified, 10 with vesicoureteral reflux and 1 with a ureterocele. For identification of treatable problems the predictive value of a positive test was: (1) fever, 10 of 24 (41.7%); (2) abnormal D-deaminoarginine vasopressin renal concentrating ability, 8 of 24 (33.3%); (3) serum C-reactive protein greater than or equal to 1.0, 8 of 25 (32.0%); (4) Elevated urine N-acetylglucosaminidase, 5 of 16 (31.2%); (5) erythrocyte sedimentation rate greater than or equal to 25, 6 of 21 (28.6%); and (6) age less than 5 years, 10 of 43 (23.3%). Absence of fever denotes a low risk (less than 3%) of finding a treatable problem. Afebrile girls older than 5 years of age can have radiologic evaluation deferred until infection recurs. The presence of fever indicates a high risk of treatable urologic problems (41.7%) and warrants complete radiologic evaluation with the first urinary infection.