The generic term "Renal Osteodystrophy" is used to denote a complex of skeletal and metabolic impairments found in nephropathic patients. Neither dialytic treatment nor transplant is always capable of limiting the worsening evolution; transplantation, on the contrary, while it does not in many cases bring the phospho-calcic metabolism back to full normality, introduced new elements of imbalance arising as a result of the inevitable immunosuppressive therapy. After outlining the main post-transplant metabolic problems, the Authors discuss the manifestations of orthopaedic interest, in particular the most severe complication, i.e. aseptic necrosis.