Not only bone mineral density (BMD) is strongly associated with body weight, but also weight change infl uences BMD change. The weight change related bone change is more marked in women especially after menopause, in the elderly, in the underweight and in persons who have the history of weight cycling. Because of the health impacts of obesity, weight reduction has been often recommended in practices. Therefore various intervention methods have been tried to reduce the weight change related bone change such as hormone therapy, raloxifene, exercise, and calcium supplementation. This review summarizes the epidemiological evidences of the weight change related bone change and the associated factors.