The bisphosphonates are a class of synthetic compounds used in the treatment of various metabolic bone diseases, including hypercalcaemia of malignancy, Paget's disease, postmenopausal osteoporosis and corticosteroid-induced bone loss. Although there have been numerous studies comparing first, second and third generation bisphosphonates with placebo, there has been a paucity of comparative research investigating the effectiveness of these substances with other pharmacological agents. Still, the available evidence indicates that the bisphosphonates are well tolerated and effective therapeutic agents for various metabolic bone diseases. It seems certain that within the next 5 years, this class of drugs will emerge as one of the foremost options for treating Paget's disease and osteoporosis.