Coinfection with HCV and HIV occurs in 20% to 30% of HIV infected people in the United States. Individuals with HCV/HIV coinfection tend to have higher HCV viral loads than individuals with HCV alone. However, current evidence suggests that initiation of effective antiretroviral therapy (ART) may be associated with increases in HCV viral load. The purpose of this study is to evaluate changes in HCV viral load associated with the initiation of ART in HCV/HIV coinfected adults.