HIV and hepatitis C virus (HCV) infection are diseases that share the same risk factors and routes of transmission. For this reason, many people infected with HIV are also infected with HCV. Interferon (IFN) is a drug used to treat HCV; however, in people coinfected with HIV and HCV, IFN treatment often does not work well and can cause unwanted side effects. The purpose of this study is to evaluate the safety, tolerability, and effectiveness of IFN-free HCV treatment in HIV/HCV coinfected adults who are taking antiretroviral (ARV) therapy.