HCV infection is a major public health concern with worldwide seroprevalence estimated at 1 percent. HIV-infected adults co-infected with HCV appear to have accelerated HIV disease progression. There is little data on HCV prevalence in the pediatric HIV-infected population. This substudy will provide estimates of HCV prevalence among HIV-infected children and determine the need for future HCV natural history and treatment protocols. In addition, this substudy will archive samples from patients for future testing for other hepatitis viruses such as hepatitis G virus (HGV or GB virus C).