OBJECTIVES: Biologics are efficacious in reducing disease activity in their authorized indications, but represent a substantial cost in the healthcare systems. Etanercept is one of the biologics of election in the treatment of autoimmune diseases due to its well established safety and efficacy profile in the approved indications. The objective of this study was to assess the budget impact of introducing Benepali^®, an etanercept biosimilar, in Spain for all licensed adult etanercept indications. METHODS: A budget-impact model (BIM) was used to estimate the cost saving potential of introducing Benepali in Spain over a three-year horizon from the payer’s perspective. Current etanercept-treated population was estimated through IMS sales data (units converted to patient numbers) and the population was assumed to remain constant during the 3-year horizon. Three model scenarios with different adoption rates of Benepali vs Enbrel^®, the reference product, were developed: slow (10%; 20%; and 30% of total etanercept sales at year 1; 2; and 3), moderate (15%; 30%; 45%) and rapid (20%; 40%; 60%). Prices were obtained from published sources. RESULTS: Introduction of Benepali in the biologic treatment setting over three-year horizon resulted in projected budget-savings of: €12.3m, €18.4m and €24.5m in the slow, moderate and rapid uptake scenario respectively. This would allow for savings equivalent of 1,240, 1,860 and 2,480 patient-years for the slow, moderate and rapid uptake scenario respectively. CONCLUSIONS: The introduction of Benepali represents substantial cost-saving potential for the healthcare system in Spain. The budget impact was sensitive to Benepali market uptake rates. Mechanisms in place that can support the biosimilar uptake are essential in order to achieve these savings. These savings will contribute to healthcare system sustainability in Spain, as these could be used to treat additional patients within the same therapeutic area, fund novel therapies for other disease areas and/or potentially fund other hospital or medical department needs.