Selective estrogen receptor modulator (SERM) is an important option for postmenopausal osteoporosis. There are two SERM approved in Japan for the treatment of postmenopausal osteoporosis in women at increased risk of fracture. One is raloxifene (RLX), and the other is bazedoxifene (BZA). There are few reports concerning to the clinical efficacy and safety data. In this study, we plan to compare clinical efficacy and safety between RLX and BZA.