Osteoporosis is a major cause of disability in elderly subjects. It represents a heterogenous group of disorders of skeletal homeostasis characterized by reduced bone mass with defective skeletal function. It is a poorly understood entity for which there is at present no effective therapy. In this review, we summarize what is known about the pathogenesis of osteoporosis and discuss the available therapeutic modalities. We suggest that the future approach will be to identify risk factors and apply preventive measures in the preclinical stage of this crippling disorder.