OBJECTIVES: : To estimate annual cost-per-treated patient and treatment patterns for etanercept, adalimumab, and infliximab in Medicaid beneficiaries with Rheumatoid Arthritis (RA). METHODS: The MarketScan Medicaid Multistate Database was used to identify adult RA patients indexing on etanercept, adalimumab, or infliximab  from 2007-2011. The index date was the first index agent claim preceded by 180 days and followed by 360 days of continuous enrollment. Patients with conditions other than RA were excluded. “Continuing” patients had ≥1 claim in the 180 days pre-index for their index biologic; “new” patients did not. Cost per treated patient was calculated in the 360 day post-index period for each index agent as the total index drug and administration costs to the payer and the costs of switched-to agents, divided by the number of patients who received the index agent. Costs were based on the amount of drug used (mg) multiplied by the September 2013 Wholesale Acquisition Cost. Treatment patterns were also described. RESULTS: A total of 1,085 patients met the study criteria: 48% received etanercept (n=521); 37% received adalimumab (n=405); and 15% received infliximab (n=159). Patient characteristics were similar across treatment groups (mean age 47.4 years, 83% female). The annual cost per treated patient was lowest for etanercept ($18,466), followed by adalimumab ($20,983) and infliximab ($26,516). For all agents, annual costs were lower for new patients ($17,996 for etanercept, $18,992 for adalimumab, and $24,756 for infliximab) than for continuing patients ($19,004 for etanercept, $24,438 for adalimumab, and $28,127 for infliximab). Rates of index drug discontinuation (including switching) were 43.8%, 46.2%, and 50.0% for etanercept, adalimumab, and infliximab; switching rates were 17.5%, 20.2%, and 31.0%, respectively. CONCLUSIONS: Etanercept had a lower cost per treated patient compared with adalimumab or infliximab in both new and continuing patients among Medicaid enrollees with RA.