Renal osteodystrophy starts very early in chronic renal failure. Although vitamin D levels are normal in patients with 70-80% function, the levels are not appropriate to the prevailing biochemical milieu. Renal osteodystrophy may contribute to renal growth failure but a correlation between the degree of renal osteodystrophy and growth failure is not observed. Catch-up growth cannot be obtained over a longer period of time with vitamin D. The main reason for osteomalacia is Al intoxication. Aluminium osteopathy is more common in pediatric renal patients than anticipated. The mechanism whereby Al produces its effect on bone is uncertain. Guidelines for the diagnosis and therapy of renal osteopathy are presented. Prophylaxis of renal osteopathy can be attempted by phosphate restriction and/or vitamin D and by avoiding Al-containing drugs. All vitamin D compounds can be used for treatment and all have their advantages and disadvantages.