Background: Fibroblast growth factor 23 (FGF23), a novel bone-derived hormone that inhibits phosphate reabsorption and calcitriol production by the kidney, has uncovered primary regulatory pathways and new systems biology governing bone mineralization, vitamin D metabolism, parathyroid gland function and renal phosphate handling.Objectives: Our study investigated FGF-23 levels in patients with end-stage renal disease before and after a successful renal transplantation and their probable association with markers of bone and mineral metabolism.Methods: 40 patients were studied for 6 months and divided into two groups (hemodialysis vs renal transplantat patients).The estimations of serum FGE23 ,calcium, phosphorus, intact parathyroid hormone were performed in both groups . We compared the changes in serum FGF23 ,calcium, phosphorus, and intact parathyroid hormone in renal transplant patients 3 and 6 months after successful renal transplantation. Results: The serum FGF23 decreased significantly after renal transplantation. i PTH and P levels also decrease significantly after renal transplantation, while Ca increase. Conclusion: FGF23 are markedly increased in patients with end stage renal disease associated with increase in phosphorous and i PTH levels . FGF-23 levels decrease dramatically after successful renal transplantation and remain within normal limits when graft function is good. iPTH and P levels also decrease significantly after renal transplantation, while Ca increase.