Osteoporosis is a disorder of ageing that shares with other disorders of ageing a multifactorial pathogenesis. The important factors for osteoporosis include the diet, life-style and intercurrent factors such as disease. However, it is clear that loss of ovarian function is an important determinant of bone loss, and oestrogen appears to be the key factor involved. Thus, not only does loss of ovarian function result in bone loss, it can be stopped by adequate oestrogen intervention. Numerous techniques are available to measure bone mass non-invasively and to estimate the risk of future fracture. Thus, for the postmenopausal woman who is concerned about osteoporosis, and who is willing to accept intervention to prevent the disease, bone mass measurement allows the clinician to determine the risk of future osteoporotic fracture and to provide intervention if required. Future studies may elucidate whether determination of skeletal remodelling using biochemistry adds significantly to risk determination. This may be required when considering agents other than oestrogen for intervention among asymptomatic women, as these agents primarily affect the skeleton, while the effects of oestrogen are wide ranging in the body.