Within weeks after SCI, there is a marked increase in bone resorption (breaking bone down) with a decrease in bone formation (adding new bone) and this is responsible for the significant loss in bone mass. Bisphosphonates are a group of medications that are used to prevent declines in bone mass or treat low BMD; they act to slow down excessive bone resorption. They are generally divided into two types, those with or without nitrogen; each type has a different mechanism of action. Etidronate, Clodronate and Tiludronate do not contain nitrogen while Pamidronate, Alendronate, Ibandronate, Risedronate and Zoledronate contain nitrogen. Etidronate (Didrocal), Alendronate (Fosamax) and Risedronate (Actonel) are oral bisphosphonates, which are currently approved for the treatment of postmenopausal osteoporosis in Canada (Brown et al. 2002). Clodronate (Benefos or Ostac) is available intravenously (IV) and orally for the treatment of osteoporosis.  Tiludronate (Skelid) is available in oral form in the United States. Zoledronic acid (Zoledronate) is a newer once yearly bisphosphonate which is administered via IV infusion. Concurrent supplementation with calcium and vitamin D have been important additions to bisphosphonate therapy for other medical conditions (such as post-menopausal osteoporosis) (Brown et al. 2002) and should be considered when prescribing oral bisphosphonates although the concurrent administration of all three compounds has not been prospectively evaluated.