Prevention of osteoporosis is better than cure. This intuitive wisdom is strengthened by knowledge that osteoporosis due to gonadal deficiency is associated with a disruption of skeletal architecture that is irreversible by current treatments. Moreover, it is commonly assumed that bone is lost more slowly in later life than in the several years after the menopause, so that factors other than decreasing bone mass are assumed to be of greater importance for fracture risk. With the exception of fluoride, current treatments have not been shown to restore skeletal mass in patients with osteoporosis. These views have suggested that the management of osteoporosis in the elderly is of limited value and have reinforced the importance of preventive measures. Notwithstanding, there are several reasons for believing that intervention late in the natural history of bone loss is worthwhile. Whereas cross-sectional studies suggest that bone loss declines in later years, prospective studies indicate that bone loss is progressive and indeed accelerates in extreme old age. Moreover, the measurement of bone mass predicts future fracture in the elderly as effectively as it does at the time of the menopause. There are also several reasons why preventive approaches at the time of the menopause have limited applicability. Since current preventive treatments cannot be given indefinitely, a crucial question concerns the extent to which reversal of effect occurs after treatment withdrawal. If catch-up bone loss does occur, it decreases markedly the cost-effectiveness of therapeutic intervention at the menopause and provides a convincing rationale for the use of interventions at a much later age. The optimum age for starting treatment is not yet determined but might be best directed 15 or so years after the menopause, well before the mean age of hip fracture. Since hip fracture provides the greatest socioeconomic impact of osteoporosis and since evidence is accumulating that treatments favorably affect hip fracture risk, it is suggested that greater attention should be given to the management of osteoporosis in the elderly.