OBJECTIVES: Compare costs of privately-insured oxymorphone extended-release tablet (“oxymorphone”) users with those of oxycodone  controlled-release tablet (“oxycodone”) users, from an employer’s perspective. METHODS: Patients, ages 18+, with ≥1 claim for oxymorphone/oxycodone during Q2:2006-Q4:2009 were identified in de-identified private payer claims data and observed from the first such claim (“index date”) until the earliest of: use of comparator drug; end of continuous eligibility; or 12 months (“study period”). Continuous eligibility was required throughout a 6-month baseline period and ≥1 month after the index date. Patients with claims for any formulation (extended-release or otherwise) of the comparator drug during the first 30 days of the study period were excluded, as were patients pregnant during the baseline/study periods. Study period risk-adjusted costs were estimated per patient-month using generalized estimating equations controlling for baseline demographics, resource use, and costs. Medical/drug (direct) costs paid by private insurers were reported for patients ages 18-64 (N = 8,354) and 65+ (N = 3,515) as well as subsets of each without cancer during the baseline/study periods (N = 7,090 and N = 2,444, respectively). Medically-related absenteeism and disability (indirect) costs were reported for all employees, ages 18-64, (N = 1,313) and employees without cancer (N = 1,146). Bias-corrected bootstrapping was used to compare third-party payer costs. RESULTS: Oxymorphone users, ages 18-64, had lower drug costs ($693 vs. $763, p=0.0035) and similar medical costs ($1,875 vs. $1,976, p=0.3570) per patient-month compared with oxycodone users. Indirect costs were not different ($662 vs. $670, p=0.9370). Oxymorphone users, ages 65+, had similar Medicare supplemental drug costs ($533 vs. $588, p=0.0840) and significantly lower medical costs ($459 vs. $747, p<0.0001). Results were comparable for the subsets without cancer. CONCLUSIONS: After controlling for baseline characteristics, real-world evidence suggests that, from an employer’s perspective, oxymorphone users may incur lower monthly direct costs than oxycodone users.