Fibroblast growth factor 23 (FGF23) levels rise early in the development of chronic kidney disease (CKD) and recent studies have shown that FGF23 increases the development of left ventricular hypertrophy in these patients. Elevated FGF 23 levels are further associated with progression to end-stage renal disease, cardiac events and all-cause mortality. In animal models a blockade of FGF23 ameliorates the pathologic effect on left ventricular mass and function. Calcimimetic therapy has been shown to reduce systemic FGF23 levels, while vitamin D therapy is known to elevate FGF23. However, there is limited data on the clinical relevance of therapeutic modification of FGF23 levels in humans.