99MTc is an ideal nuclide for Pediatric use. Combined with DTPA is an adequate agent for renal studies. 15 patients with ages ranging from eight days to eleven years were studied (10 patients with congenital malformation and five with renal tumour). The dosimetric advantages, the obtention with a single nuclide dose of multiple images and the diagnostic usefulness in congenital malformation and renal tumour suggest their use.