Thirty three healthy infants and children with a family history of reflux nephropathy or vesicoureteric reflux in first degree relatives were screened for upper urinary tract abnormalities (renal scarring or pelvicaliceal dilatation) using ultrasound scanning or intravenous urography, or both. In addition, micturating cystourethrography was carried out in all infants and children under 2 years old (n = 20) and in children over 2 years old in whom abnormalities of the upper renal tract (renal scarring) had been found (n = 3). Upper renal tract abnormalities were found in four of the total of 33 children (12%) and vesicoureteric reflux in 12 of the 23 who underwent micturating cystourethrography (52%). Screening of infants and children was acceptable to parents. This approach has enabled the diagnosis of vesicoureteric reflux to be made in an appreciable number of children before the development of urinary tract infections and reflux nephropathy. Prospective follow up of this group will provide more information about the natural history of sterile vesicoureteric reflux.