Osteoporosis has been defined as "a progressive systemic disease characterized by low bone density and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture." Osteoporosis and the consequences of compromised bone strength--particularly vertebral and hip fractures--are a significant cause of frailty, and increased morbidity and even mortality and hence are a serious and costly public health problem in the elderly population. However, due to remarkable advances in basic and clinical research and in drug design, development, and testing, a number of efficacious, evidence-based options are available for the prevention and treatment of osteoporosis. These options extend far beyond estrogen/progestin therapy and include lifestyle and dietary changes such as increasing weight-bearing activity, enhancing calcium and vitamin D intake, as well as incorporating pharmacologic agents such as the bisphosphonates and selective estrogen receptor modulators (SERMs) such as raloxifene. In addition to its efficacy in increasing bone mineral density and reducing vertebral fractures by almost 40% in women with osteoporosis, the SERM raloxifene appears to promote a cardioprotective profile and to offer some protection against breast cancer. The potential of raloxifene to prevent or delay the development of a number of chronic diseases of aging such as osteoporosis, cardiovascular disease, and perhaps even Alzheimer's disease has stimulated the development and refinement of subsequent generations of SERMs aimed at maximizing beneficial effects in a wide variety of tissues while eliminating deleterious outcomes and side effects.