Vitamin D has many important roles in calcium and phosphorus metabolisms, the prevention of the cancer, therapeutic effects of autoimmune disease, and the protective effects on the atherosclerotic cardiovascular disease and diabetes. These functions are quite essential factors for the treatment of anti-aging medicine. We had given 1,000 IU/day vitamin D(3) to the patients who had low vitamin D levels in their blood and confirmed the increased vitamin D levels into the optimal range after the treatment. To keep the normal functions of the bone mineral metabolisms and the immune function, it is clinically relevant to detect the vitamin D levels in the blood and support these levels using supplements in the vitamin D deficient patients. Vitamin D is now one of the most essential vitamins in the anti-aging medicine.