There has been significant progress in the management of osteoporosis in recent years, resulting in a greater choice of therapeutic interventions for the physician. Nearly all of the treatments currently available are antiresorptive agents, which prevent bone loss and, in some cases, have been shown to reduce fracture risk. Some of these agents appear to have site-specific effects in the skeleton and may therefore not protect against all types of osteoporotic fracture. However, other drugs, such as hormone replacement therapy; and possibly bisphosphonates, appear to reduce fracture risk in both the spine and hip. The optimal timing and duration of therapy for osteoporosis remain to be defined and will differ between agents. There is increasing evidence that the changes in bone mass induced by treatment do not always predict the corresponding changes in fracture rate. Thus, significant reductions in fractures may occur with antiresorptive therapy despite very small changes in bone mass, while large increases in bone mass may be associated with reduced bone strength and unchanged or increased fracture rates. Finally, the demonstration that relatively short term interventions can substantially reduce fracture rates, even in the very elderly in whom bone mass is almost universally low, provides the rationale for a more aggressive approach to treatment in patients with established disease.