The vast majority of small segmentally scarred kidneys seen in childhood are now recognised to be associated with vesicoureteric reflux and the term "reflux nephropathy" has been accorded general recognition as a description of this renal lesion. With regard to the pathogenic mechanisms responsible for the scarring process, the possible roles of intrauterine renal maldevelopment, bladder dysfunction, functional urinary obstruction and infection in relation to vesicoureteric reflux and the associated phenomenon of intrarenal reflux must all be considered. It is probable that in different clinical circumstances all of these factors may be important to varying degrees and discussion of their contributions to the spectrum of reflex nephropathy is the basis of this communication.