Osteoporosis and subsequent fracture are a major cause of morbidity and mortality. It is defined by low bone mass, and has many etiologies with different patterns of bone loss. Corticosteroid therapy is a contributor to the development of osteoporosis. Steroids cause bone loss by a variety of complex mechanisms. It has been suggested that patients initiating steroids should receive preventative therapy (calcium, Vitamin D, estrogens or bisphosphonates).