Renovascular hypertension (RVH) is responsible for 10% of arterial hypertension in children. The early diagnosis of RVH permits specific treatment leading to the cure of hypertension and avoidance of parenchymal damage. Captopril renal scintigraphy (CRS) provides information on the renovascular cause of the arterial hypertension. To validate the usefulness of CRS in hypertensive children, clinical, scintigraphic, and radiological data from 20 patients (mean age 6.1+/-5.5 years) were reviewed. Two patients were newborns. All had renal ultrasound scans and 9 had aortograms. In 7 children, RVH was confirmed by angiography, and CRS was positive for RVH in 6 of these. CRS was negative for RVH in 12 of 13 children without RVH. CRS was non-diagnostic in 3 children with abnormal baseline renal scintigraphy and severely decreased relative renal function ( <35%), 1 of whom had RVH. No side effects of captopril renography were observed. Captopril renography provides a logical, non-invasive, safe, and cost-effective approach in the evaluation of children suspected of having RVH.