Glucocorticoids (GC) are widely used for anti-inflammatory and immunosuppressive therapy. Thirty to 50% of GC-treated patients develop osteoporosis. Potential mechanisms of GC-induced osteoporosis (GC-OP) include abnormalities in calcium balance, vitamin D metabolism, parathyroid hormone release and activity, prostaglandin E2 and cytokine synthesis, interference with c-fos and p-53 expression in osteoblasts, and hypogonadism. Early diagnosis and detection of patients at risk are accomplished with rapid, safe and non-invasive bone density measurements. Preventive measures include maintaining a positive calcium balance, vitamin D supplementation (if indicated) and treatment of hypogonadism. The shortest duration and the smallest doses possible of GC for a particular condition are advisable. For high-risk patients and those with established GC-OP calcitonin or bisphosphonate therapy is recommended.