Chronic kidney disease-mineral and bone disorder (CKD-MBD) progressively develops from predialysis period. Phosphorus retention, hypocalcemia, and disturbance in activation of vitamin D lead to CKD-MBD. It is important to control the metabolic disorder, so that PTH level can be reduced. Recently, activated form of vitamin D plays important roles not only in calcium metabolism but in ontogenesis, cell differentiation, lipid metabolism and immunoregulation. Vitamin D replacement may be necessary because vitamin D is deficient in patients with predialysis CKD. However, there are possibilities that administration of vitamin D and/or calcium carbonate cause vascular calcification and decrease in residual renal function.