An overview of intermittent cyclical therapy with oral etidronate disodium in the treatment of postmenopausal osteoporosis is given. Etidronate has been used successfully in the treatment of Paget's disease and for the prevention and treatment of heterotopic ossification after hip replacement and spinal cord injury. It is approved for the treatment of postmenopausal osteoporosis in many European countries, Canada and Australia. Studies of such therapy indicate that etidronate significantly increases bone mass, reduces the risk of future vertebral fracture, and is safe and generally well tolerated.