Osteoporosis is a common skeletal condition that results in significant morbidity, mortality and health care costs. There is an increased awareness of bone health in people with severe mental illness (SMI). These people appear to be at a higher risk of low bone density and fracture, and also have a poorer outcome following hip fracture. The reason for the increased risk of osteoporosis is multifactorial and includes general as well as disease-specific factors, such as antipsychotic medication and hyperprolactinaemia. Clinical history and examination followed by dual energy x-ray absorptiometry are required to assess the risk of osteoporosis. Therapies should begin with lifestyle measures, such as physical activity and dietary supplementation, with the use of bone-specific agents reserved for those at high absolute risk.