OBJECTIVES: Multiple sclerosis (MS) is a chronic, neurodegenerative inflammatory disease of the central nervous system. In Spain, the prevalence rate of MS is estimated to range between 53 and 58 cases per 100,000. At disease onset, relapsing-remitting MS (RRMS) is diagnosed in approximately 60% to 85% of MS patients. Based on the available evidence, pharmacological costs of disease modifying drugs (DMD) represent the highest proportion of direct health care costs. In order to ensure sustainability of the health system is crucial to analyze pharmacological cost of DMD used in the treatment of RRMS from the perspective of the health system. METHODS: A direct medical costs analysis model was developed to assess pharmacological costs per patient and year of treatment with DMD. Therapeutic alternatives assessed were: interferon (IFN) β-1a intramuscular, IFN β-1a subcutaneous 22 µg, IFN β-1a subcutaneous 44 µg, IFN β-1b subcutaneous, IFN β 1-b subcutaneous, glatiramer acetate, natalizumab and fingolimod. Dosages for each drug were those described in summary product characteristics. Pharmacological costs were obtained from database of General Council of Official Colleges of Pharmacists (BotPlus) consulted at May 2012. Costs were expressed as ex-factory price applying 7.5% discount according to RDL 8/2010. RESULTS: Pharmacological costs per patient and year of treatment for each one of the therapeutic alternatives assessed were: 10,050.74€ for IFN β-1a im; 9,357.23€ for IFN β-1a sc 22µg; 14,035.64€ for IFN β-1a sc 44µg; 9,761.56€ for IFN β-1b sc; 9,420.38€ for glatiramer acetate; 19,683.12€ for natalizumab and 19,292.90€ for fingolimod. CONCLUSIONS: Due to actual socioeconomic climate and the recent measures of pharmaceutical costs containment, when selecting the most appropriate therapeutic option additionally to efficiency criteria, the economic impact on pharmacy services should be also considered. This analysis is particularly relevant in the case of chronic diseases with a high socioeconomic impact, as the RRMS.