One of the main problems in patients with chronic kidney disease (CKD) is a disturbance of calcium-phosphorus metabolism, especially in chronic hemodialysis. Besides classical endocrine axis parathyroid-kidney, in recent years was established the existence of a new endocrine axis the bone-kidney, which gives a better explanation of the calcium and phosphorus metabolism abnormalities, pathophysiology of secondary hyperparathyroidism in CKD. FGF23 is a circulating factor synthesized in osteocytes. It inhibits renal phosphate reabsorption and activity of 1-alphahydroxylase. Anti-aging Klotho protein is a potent co-factor of FGF23. This review presents the mechanisms of the interaction of these elements of the newly discovered axis in normal settings and secondary hyperparathyroidism.