OBJECTIVES: In patients with chronic infection with hepatitis C virus (HCV) genotype 1 who did not achieve a sustained response to the standard therapy with peginterferon/ ribavirin (PR) the combination of boceprevir (B) or telaprevir (T) plus peginterferon alpha/ribavirin have shown to produce a higher rate of sustained virologic response (SVR) than the retreatment with PR. The aim of this study is to assess the cost effectiveness of these two (BPR and TPR) antiviral regimens. METHODS: We developed a Markov model to describe the clinical history of previously treated HCV genotype 1 patients who did not achieve SVR in which one cohort (1) receives PR for 4 weeks followed by BPR for 32 weeks and, those patients with a detectable HCV RNA level at week 8 receive PR for an additional 12 weeks; cohort 2 patients receive 12 weeks TPR followed by 36 weeks PR. 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 RESPOND 2 and REALIZE 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: The combination BPR increases life expectancy by 0.60 years and quality adjusted life years (QALY) by 0.89 years compared to TPR. BPR is cheaper than TPR (-23,428 Brazilian Reais). CONCLUSIONS: In Brazil, for the treatment of previously treated patients with HCV genotype 1 infection boceprevir plus peginterferon alpha/ribavirin is dominant compared with telaprevir plus peginterferon alpha/ribavirin.