Osteoporosis is one of most common metabolic bone disease that the incidence and related fractures are increasing. Early diagnosis, prevention and treatment are becoming a big issue recently. Diagnosis of osteoporosis previously was from indirect assessment of bone mass by X-ray film of proximal femur, spine or calcaneus lateral, or from histologic grading of iliac bone biopsy. But recently development of dual energy X-ray absorptiometry (DXA) enabled noninvasive and precise assessment of bone mass, and measurement of biochemical bone markers from blood and urine are used as dynamic index of bone metabolism. These diagnostic methods can be used for assessment of fracture risk, and response of medication in osteoporotic patients.