Over 4.5 million people in the United States have chronic hepatitis C virus (HCV) infection, yet only 50% of HCV-infected individuals are diagnosed and ~15% receive curative treatment. HCV-related stigma has been identified as an important and understudied barrier to HCV care. Stigma is a social-process, linking individual attributes/behaviors to negative stereotypes. Stigma in healthcare is associated with poor health outcomes and decreased quality of life. Moreover, healthcare stigmas may intersect with stigmas of other personal attributes, intensifying patient experiences of disease-related stigma and social marginalization. To date, no validated and standardized instrument exists to measure perceptions of stigma among patients with chronic HCV infection, limiting efforts to identify, measure, and intervene upon the impact of stigma. To address existing knowledge gaps, we conducted an explanatory mixed-methods study across five Philadelphia healthcare clinics to: 1) revise and validate the Berger HIV Stigma Scale- a validated HIV stigma measure- for use among patients with HCV; 2) identify factors associated with HCV-related stigma; and 3) connect subjective experience of HCV-related stigma to HCV Stigma Scale (HCV-SS) scores. Our mixed-methods approach included a cross-sectional survey instrument (n=270) and semi-structured interviews among a subset of participants (n=23) who completed the survey instrument. We evaluated the validity of the HCV-SS using factor analysis and item response theory. Analyses evidenced a unidimensional factor solution, yielding a 33-item scale with good reliability (=0.957) and construct validity. Qualitative content validity analyses identified additional salient themes that inform HCV-related stigma experiences, chiefly familial support and associated injection drug-use stigma. We then used multivariable linear regression to analyze associations among HCV-related stigma and hypothesized demographic, behavioral, and clinical determinants. We hypothesized that additional stigmatized attributes, such as HIV coinfection and history of injection drug use, may augment experiences of HCV-related stigma. We found that most participants experienced stigma associated with their HCV diagnosis. Determinants of HCV-related stigma differed substantially between HCV-monoinfected and HCV/HIV-coinfected participants. The generation of a validated and standardized scale to measure HCV-related stigma and identify determinants improves understandings of stigma experienced by patients with HCV-infection, which can inform interventions to increase rates of HCV diagnosis and treatment.