Purpose: We sought to determine the frequency and types of prophylaxis for osteoporosis that were prescribed to outpatients who were receiving chronic glucocorticoid treatment and to identify the patient and provider characteristics that were associated with the use of prophylaxis. SUBJECTS AND METHODS: We identified 215 adult outpatients at San Francisco General Hospital who had received a prescription for prednisone (or its equivalent) at a daily dose of at least 5 mg for at least 1 month. Patient demographic characteristics, the diagnosis for which glucocorticoids were prescribed, comorbid illnesses, and medications were determined by chart review. Characteristics of the patients who were prescribed prophylaxis were compared with those of patients who were not prescribed prophylaxis. RESULTS: Prophylaxis for glucocorticoid-induced osteoporosis was prescribed to 58% of patients. Patients prescribed prophylaxis were older (mean [± SD] age of 50.0 ± 13.9 versus 44.5 ± 13.6 years, P = 0.004), more likely to be female (69% versus 40%, P < 0.0001), postmenopausal if female (84% versus 56%, P = 0.002), have more comorbid illnesses (63% versus 29%, P = 0.001), and take multiple medications (66% versus 45%, P = 0.002). Patients attending the rheumatology clinic were 1.6 times more likely to receive prophylaxis than those attending other clinics (P < 0.0001). The strongest predictor of prophylaxis was postmenopausal state. In premenopausal women, the independent predictors of prophylaxis were being treated in the rheumatology clinic and the presence of comorbid illnesses, whereas comorbid illnesses was the only independent predictor of prophylaxis in men. CONCLUSIONS: Educational efforts should be directed toward increasing awareness of the importance of glucocorticoid-induced osteoporosis and its prevention.