Introduction: Hepatitis C virus (HCV) infection is a major leading cause of morbidity and mortality worldwide. Per-sistent HCV infection is associated with major liver complications such as liver failure, liver cancer and fatality. It is estimated that 5.6 million people who inject drugs (PWID) were chronically infected with HCV globally, meanwhile, 59% of those diagnosed as HCV in Malaysia were PWID. The objective of this study was to determine the social determinants of HCV infection among PWID in Negeri Sembilan, Malaysia. Methods: A cross-sectional study was conducted based on stratified proportionate to size sampling among registered Methadone Maintenance Therapy (MMT) clients with PWID attending health clinics in Negeri Sembilan from February 2018 to July 2018. All eligi-ble respondents were randomly selected. Data were collected using an interviewer-guided questionnaire and was analysed using Statistical Package of IBM SPSS version 23. Independent T test and Chi-square test (χ2) were used to determine the associations between the variables. Results: Majority of the respondents in this study were between 20 and 63 years of age, Malay (90.1%) and infected with HCV (89%). There was a significant association between the respondent’s age (p