OBJECTIVES: To assess the budget impact of the treatment for Relapsing Remitting Multiple Sclerosis (RRMS), interferons, and glatiramer acetate, from the National Health System (NHS) perspective METHODS: A budget impact model was designed to compare the cost of RRMS treatment in different settings, using a 5 year time-horizon, considering different percentages of administration of each medication. A reference setting o base case using all the available first line treatments (interferons and glatiramer acetate) was compared with 5 alternatives scenarios excluding each one of these treatments. The cost analysis (2010 euros) includes direct medical resources (drugs, administration, visits, disease management, diagnostic tests). Unitary cost data was obtained from the health costs database e-Salud and drugs Catalogue  RESULTS: Considering a cohort of 22,255 patients with RRMS, the mean global budget impact per year would be € 260.775.470 in the base case. The setting that excluded glatiramer acetate increases the budget impact in a 3.23% (€ 372 per patient per year). Pharmacological costs were the key drivers of total cost (90%).  CONCLUSIONS: The use of glatiramer acetate in the first-line-treatment of RRMS patients is a cost-saving strategy, which may decrease the budget impact from the NHS perspective in Spain