OBJECTIVES: To estimate costs of managing corticosteroid (CS)-related adverse events (AEs) within a systemic lupus erythematosus (SLE) population. METHODS: A retrospective claims analysis (January 1, 2000–June 30, 2010) was conducted within an SLE population to evaluate the risk of known CS-related chronic and acute AEs among CS users and non-users by utilizing Cox proportional hazards models adjusting for patient characteristics, SLE severity, other SLE treatments, and AE-related risk factors. Associated costs were computed for AEs where the risk was significantly different among CS users compared to non-users. CS users having a chronic AE were followed for 12 months post-AE date to capture total costs, which were compared to total costs of CS users who did not have a chronic AE during the same time period. Predicted annual costs were generated using generalized linear models controlling for baseline characteristics. The incremental difference in annual costs among the two groups was considered attributable to the AE. For patients having an acute AE, disease-specific costs were calculated over a 12-month timeframe post-AE date. RESULTS: SLE patients receiving CS were more likely to develop chronic AEs (ie, cataracts, sleep disturbances, hypertension, type II diabetes, migraine) and acute AEs (ie, pneumonia, herpes zoster, fungal infections, nausea/vomiting). The average annual cost for managing AEs was highest for type II diabetes ($9763), followed by hypertension ($8774), sleep disturbances ($5599), migraine ($3591), cataracts ($2407), herpes zoster ($2079), pneumonia ($1726), nausea/vomiting ($1357), and  fungal infections ($857). When applying base rates and increased risk estimates of each AE to the cost estimates, it costs an additional $784/year per CS user to manage known CS-related AEs compared to CS non-users. CONCLUSIONS: Within an SLE population, CS treatment is associated with additional costs of $784/year due to management of CS-related AEs. Providers and payers should consider these potential costs of CS when making treatment decisions.