The proposed project is a phase I clinical trial designed to evaluate the safety, tolerability and immunogenicity of a therapeutic hepatitis C virus (HCV) DNA vaccine strategy that combines the HCV DNA vaccine with Interleukin-12 and is administered by electroporation. The trial aims to determine the optimal dose of IL-12 for vaccine immunogenicity based on induction of HCV-specific cellular immune responses (IFN? production by CD8 T-cells and viral load reduction). Specifically, this Phase I trial will test the candidate vaccine, a genotype 1a/1b DNA vaccine encoding for non-structural (NS) HCV antigens (NS3 /NS4A, NS4B and NS5A) alone or with increasing doses of Interleukin 12 (IL-12) adjuvant, at 4 time points, to patients with chronic HCV. This study requires screening 32 participants and will take approximately 22 months to enroll and evaluate 24 evaluable participants for the primary and secondary endpoints.