OBJECTIVES: In previously untreated adults with hepatitis C virus (HCV) genotype 1 infection the combination of boceprevir (B) or telaprevir (T) plus peginterferon alpha/ribavirin (PR) have shown to produce a higher rate of sustained virologic response (SVR) than peginterferon alfa/ribavirin (PR). The aim of this study is to assess the cost effectiveness of these two antiviral regimens. METHODS: We developed a Markov model to describe the clinical history of CHC genotype 1 patients in which one cohort (1) receives PR for 4 weeks followed by BPR for 24 weeks and those patients with a detectable HCV RNA level between weeks 8 and 24 receive PR for an additional 20 weeks; cohort 2 patients receive TPR for 12 weeks followed by PR for 12 weeks and those patients with a detectable HCV RNA level between weeks 4 and 12 receives PR for an additional 24 weeks. All patients are followed for their expected lifetime. The reference patient is 30-year-old with CHC without cirrhosis. The SVRs to BPR and TPR cohorts came from SPRINT 2 and ADVANCE studies. Quality of life for each health state was based on literature. Costs for each health state were based on three Delphi panels, one with hepatologists, one with intensivists and another with oncologists. Costs in 2011 Brazilian Reais and benefits were discounted at 3%. RESULTS: BPR increases life expectancy by 0.78 years and quality adjusted life years (QALY) by 1.20 years compared to TPR. BPR is cheaper than TPR (-25,924 Brazilian Reais). CONCLUSIONS: In Brazil, for the treatment of previously untreated adults with HCV genotype 1 boceprevir plus peginterferon alpha/ribavirin is dominant compared with telaprevir plus peginterferon alpha/ribavirin.