FGF23 acts as a phosphaturic hormone, a suppressor of vitamin D and has some non-consensual effect on parathyroid hormone (PTH). FGF23 has a specific receptor but needs a co-factor, klotho protein, to perform the majority of its functions. Serum klotho levels in CKD are low, influencing the resistance to FGF23 activity. What happens in transplanted patients is not yet totally understood; some studies pointed out for endothelial dysfunction and cardiovascular disease mediated by these factors in the transplant setting. Besides, graft loss and mortality were related with high serum levels of FGF23 and with bone mineral density loss but their relation with histological bone disease is unknown.