OBJECTIVES: Currently the clinical protocols for the treatment of relapsing-remitting multiple sclerosis of the public sector in Brazil do not differentiate the interferonβ options available (Avonex®, Betaferon® or Rebif®). Considering the data presented in a meta-analysis by Filippini et al in 2013, a budget impact analysis was developed to understand the impacts of recommending the use of Rebif® as the interferon of choice. METHODS: A transition model was developed under the assumption that patients experiencing a relapse would have a 50%  chance of switching to another line of therapy. Each treatment relapse rate was calculated from the Philippini 2013 meta-analysis information regarding the risk of having a relapse in 24months, using the formulae developed by Zhang and Yu, 1998. Such formula calculates the relative risk from odds ratio information using the “assumed control risk”, which was calculated by the pondered average rate of relapses occurring in all related trials’ placebo arms. Only 2014 direct medical costs were considered, including medications and hospital costs obtained at the DATASUS database. The number of patients was estimated by the number of treatments provided at the year of 2014, and the time horizon was defined as 5 years. Market shares were calculated from the 2014 public purchases information and the compared scenarios were the current practice versus an alternative scenario where Rebif® was considered the interferon of choice. RESULTS: Current scenario represents BRL1,288.32 million in first and second line medications, BRL219.00 million in third line medications, and BRL20.46 million in relapses’ acute care. Alternative scenario could represent BRL1,300.51 million in first and second line medications, BRL201.16 million in third line medications and BRL19.94 million in relapses’ acute care. CONCLUSIONS: Total savings with the new scenario were BRL 6.16 million, mainly by reducing relapses and delaying the start of more expensive third line medications.