In 1,076 women the forearm bone mineral content (BMC) had been measured with single photon gamma absorptiometry (SPA) 10-16 years ago. The incidence of fractures incurred in the ensuing years (1975-1985) was recorded. The BMC had been significantly less in those women who were to have the types of fractures that are related to bone fragility but only in women measured during the first post- menopausal decades. From age 50-69, diminished BMC at the distal forearm site was associated with a threefold increase of relative risk whereas at the proximal site there was about a sixfold increase in relative risk. This association was not evident in the population over 70 years of age because of a high frequency of fractures (mostly of the spine) in subjects with relatively high BMC values. Body weight and grip strength were significantly lower in the fracture group over 70 years of age.