Dental examination of 73 paediatric patients with nephrotic syndrome and 49 with chronic renal failure revealed enamel changes of permanent teeth in about 50%. They consisted usually of white discolorations and hypoplasia of enamel. In nephrotic patients they were observed particularly after the administration of high doses of corticosteroids. In patients with renal failure enamel changes occur very early. Their location was usually compatible with an insult on enamelisation at the time of manifestation of kidney disease. The prevalence of caries was almost twice as high in patients with nephrotic syndrome than in those with renal failure.