Interferon-alpha (IFN-alpha) mono-therapy is largely ineffective for most of the hepatitis C virus (HCV)-infected patients that receive it. The addition of ribavirin to IFN therapy has increased the response rate dramatically. While many factors are implicated in determining the success rate for IFN therapy, viral genotype seems to play a crucial role. Examining differences in viral gene sequences has and will continue to advance our understanding as to how HCV and other viruses circumvent the IFN response. Here we review the different ways that HCV evades the immune response elicited by IFN.