Using mice with parathyroid-specific knockout of αKlotho or Fgfr genes, we have shown here that FGF23 contributes to the induction of secondary hyperparathyroidism associated with CKD, and that the function of FGF23 in the parathyroid glands is mediated by theαKlotho/FGFR complex. Here, FGF23 is linked to chronic kidney disease.