Long-term treatment with glucocorticoids can result in drug-related complications, among which osteoporosis is one of the most frequently encountered problems. Each patient treated with a dose of 7.5 mg or more of prednisone daily for at least 3 months can be affected. During the prolonged steroid use bone formation is inhibited while its resorption increases and negative calcium balance with secondary hyperparathyroidism occurs. In the affected bone, multiple focuses of osteomalacia and avascular necrosis are also described. The bone fracture risk is much higher than it can be suspected on the basis of bone mineral density (BMD) assessment. Therefore, in glucocorticoid-treated patients with only slightly decreased BMD (osteopenia according to the WHO criteria) treatment with antifracture agents should be initiated as soon as possible. Indication for therapy is a T-score of -1.5. Calcium supplementation with vitamin D represents an initial step of prevention and treatment. A first-line treatment effective in preventing bone fractures involves aminobisfosfonates such as alendronate and risedronate. Other effective agents are also estrogens, testosterone, selective estrogen receptor modulators and anabolic agents (parathormon, dehydroepiandrosteron, strontium ranelate).