Drug users account for a disproportionately large burden of hepatitis C virus (HCV) infection. However, HCV treatment adherence rates in drug users may be suboptimal in patients who use drugs regularly during HCV treatment. Because HCV treatment is most effective when patients adhere to at least 80% of the prescribed treatment regimen, interventions to improve HCV treatment adherence need to be developed and evaluated. The investigators designed the HCV DOT trial to test the efficacy of two versions of modified directly observed HCV therapy provided on-site at a methadone clinic. The primary objective of this trial is to determine whether enhanced DOT with both pegylated interferon alfa-2a plus ribavirin (PEG/RBV-DOT) is more efficacious than standard DOT with weekly provider-administered pegylated interferon (PEG-DOT) and self-administered ribavirin for increasing adherence and improving HCV treatment outcomes. The investigators hypothesize that PEG/RBV-DOT is associated with increased adherence and rates of sustained viral response compared with PEG-DOT.

Inclusion Criteria:

• HCV-infected
• receive HCV medical care at the methadone clinic
• plan to initiate HCV treatment on-site within the next 3 months
• psychiatrically stable as determined by HCV treatment provider and/or on-site psychiatrist
• attend the methadone clinic between three and six days per week to receive methadone
• stable dose fo methadone for two weeks prior to the baseline visit

Exclusion Criteria:

• unable or unwilling to provide informed consent
• currently receiving HCV treatment
• primary HCV care provider does not agree to their participation in the trial
• psychiatrically unstable