It has been argued that women must be screened and treatment begun for osteoporosis at menopause, since there is an irreversible and substantial loss of bone in the 10 years following menopause. Screening and treatment of women after age 65 has been understudied, since it has been assumed that bone loss in elderly women is slow and treatment would be ineffective if initiated at that time. A number of recent results now suggest that the value of screening elderly women should be reassessed. First, several large studies have demonstrated that we can identify elderly women at high risk of future hip and other fractures using bone mass, particularly bone mass at the hip, as well as other risk factors. Second, it has been shown in recent longitudinal studies that bone loss not only continues but accelerates in old age. Third, a continuing strong association of bone mass with fracture risk, even after age 80, suggests that therapies that slow bone loss will reduce fracture risk in this age group. Lastly, there is a slowly growing body of direct evidence that therapy can reduce fracture risk in the elderly. In addition, findings in a number of studies suggest that there is less necessity to screen and treat at menopause for a number of reasons. First, recent longitudinal results suggest that bone loss at menopause is less accelerated than had been believed and that the accelerated phase is briefer. Second, there is some evidence that elderly women treated with antiresorptive agents experience an increase in bone mass, with the result that an 80-year-old woman who has been treated since menopause has only slightly higher bone mass than an 80-year-old who began treatment at age 65. Lastly, at age > or = 65 we can more precisely estimate the risk of hip fracture and therefore target treatment more cost-effectively. We conclude that there is ample justification for screening and treating elderly women. Furthermore, cost-effectiveness analyses that compare early and late screening and treatment options, as well as combinations of the two, must be performed in order to develop an optimal screening and treatment algorithm for osteoporosis.