Vitamin D and K are nutrients necessary for bone health. Vitamin D insufficiency, which is milder than vitamin D deficiency to cause rickets and osteomalacia, is associated with increased fracture risk. Serum 25 (OH) D concentration, a good marker for vitamin D status, must be higher than the traditional held consensus of 20 ng/mL for bone health. Daily dose of 800 IU or higher is considered to be necessary for fracture prevention. Recently, much attention has been paid on extra-hepatic actions of vitamin K including bone. Elevated serum concentration of undercarboxylated osteocalcin, a sensitive marker for vitamin K inadequacy in the bone, is a risk factor for fracture independent of bone mineral density.