Objective. To characterize glucocorticoid use and patterns of osteoporosis prevention therapies among a large US national cohort. Methods. Health maintenance organization (HMO) members who were receiving chronic glucocorticoid therapy (> 90 day supply) within a 3 year observation period were identified along with their prescribing physicians. Receipt of anti-osteoporotic prescription therapies and bone mass measurement was determined. Multivariable analyses were used to define significant predictors of these preventive interventions. Results. We identified 2378 HMO members who filled prescriptions for at least a 90 day supply of glucocorticoids, but had not filled a glucocorticoid prescription in the prior 90 days. In women over age 50, use of anti-osteoporotic therapies and bone mass measurement was 41% and 16%, respectively. Glucocorticoid-prescribing physicians were identified for 878 (37%) of these glucocorticoid users, and internal medicine specialists (39%) and rheumatologists (20%) wrote the majority of the prescriptions for glucocorticoids. Women age 50 and over were most likely to receive a prescription anti-osteoporotic preventive therapy (OR 4.0; 95% CI 1.5-10.8). Patients with a rheumatologist prescribing their glucocorticoids were more likely than those of internists to have a bone mass measurement (OR 2.2; 95% CI 1.3-3.6) and receive bisphosphonates (OR 1.9; 95% CI 1.1-3.1), but were not more likely to receive preventive treatment overall. Conclusion. Although better than in several prior studies, we identified low levels of selected preventive care measures for chronic glucocorticoid users in a large population based cohort. Significant demographic and practice pattern variation suggests opportunities for targeted preventive interventions.