Osteoporosis is defined in adults as having a bone mineral content at the lumbar spine or hip of more than 2.5 standard deviations below the expected mean for the healthy young sex-matched population (WHO criteria). Osteoporosis and consequent fragility fractures are common problems, increasing in frequency with age. Several classes of drug of proven value in reducing the risk of osteoporotic fractures are now available. This review will examine how the evidence that treatment of osteoporosis reduces fracture risk applies specifically to older people, particularly those over 70 years of age.