OBJECTIVES: The hepatitis C virus (HCV) is one of the most common blood-borne viral illnesses in Brazil and associated with various sequelae including cirrhosis and hepatocellular carcinoma.  Treatment can be effective but also carries the risk of tolerability issues. The current study assessed the prevalence of tolerability issues among HCV patients and their association with health outcomes.  METHODS: Data were derived from the 2011/2012 Brazil National Health and Wellness Survey (N=24,000), an Internet-based health survey administered to a representative sample of the Brazilian adult population.  HCV patients with treatment experience were categorized based on the presence or absence of tolerability issues.  Patients with a diagnosis of anemia, a diagnosis of depression, or a positive screen for depression based on the Patient Health Questionnaire-9 (i.e., score of 5+) were considered to have tolerability issues.  Patients with and without tolerability issues were compared with respect to health outcomes (SF-36v2, Work Productivity and Activity Impairment questionnaire, and healthcare resource use) using regression modeling. RESULTS: N=197 patients reported a diagnosis of HCV. Of these, N=117 (53.9%) were currently using treatment (77.8% using either ribavirin and/or interferon-alfa) or had been treated in the past.  57.3% of patients (N=67) experienced a tolerability issue.  These patients had been diagnosed more recently compared with patients without a tolerability issue (13.4% vs. 6.0%, respectively, were diagnosed <5 years ago; p<.05). No other demographic and healthy history differences were observed.  The presence of tolerability issues was associated with worse health utilities (0.63 vs. 0.75), a greater level of overall work impairment (48.3% vs. 9.67% work time missed or impaired), and more hospitalizations in the past 6 months (0.81 vs. 0.13) (all p<.05). CONCLUSIONS: Anemia and depression are common tolerability issues among those with HCV in Brazil and are associated with significantly worse health outcomes.  More tolerable treatments could have significant patient and societal benefits.