Pyelonephritis in children may lead to irreversible renal damage and eventually to arterial hypertension and renal insufficiency. Inflammation plays a central role in the pathogenesis of pyelonephritis. Dimercaptosuccinic acid (DMSA) scintigraphy permits detection of acute renal lesions and renal scars with high sensitivity and specificity. In our experience 60% of patients who had acute renal lesions on DMSA scintigraphy during pyelonephritis develop scars. Young age appears to be not a risk factor, as in our experience 70% of children older than 5 years develop scars compared to 40% for children younger than 1 year. In addition, only 40% of patients who develop scars have vesicoureteral reflux. DMSA scintigraphy may provide answers to important clinical questions: what is the optimal length of treatment of pyelonephritis? Is parenteral treatment necessary? What is the best treatment of vesicoureteral reflux? DMSA scintigraphy permits therapeutical decision-making according to the renal involvement in each of our patients.