One hundred and fifty children with proven urinary tract infection who were assessed by renal ultrasound (U/S), intravenous urography (IVU) and dimercaptosuccinic acid (99mTc DMSA) scan, were studied to identify the sensitivity of each examination and the pick-up rate of renal scarring secondary to vesicoureteric reflux. Sixty-three of these children who had the examinations carried out within a 6-month period were assessed in detail. A DMSA scan is the most accurate method of detecting early renal scars in the young age group (0-2 and 2-5 years), followed by ultrasound. The examinations are equally sensitive over the age of 5. A new grading system of the severity of renal scarring is presented.