HIV-hepatitis C virus (HCV) coinfection is common and affects more than one-third of all HIV infected persons worldwide. Prevalence among risk categories varies according to shared risk factors for transmission, mainly intravenous drug use (IDU) and hemophiliacs. Chronic HCV infection seems to accelerate the course of HIV disease, resulting in a worsened clinical and immunological progression. At the same time, several studies suggest that HIV disease modifies the natural history of HCV infection, leading to a faster course of progression from active hepatitis to cirrhosis, to end stage liver disease and death. HCV infection mimics opportunistic diseases because its natural history is significantly accelerated in HIV patients. Since highly active antiretroviral therapy (HAART) has slowed the progression of HIV disease and decreased the rate of HIV associated mortality, the prognosis of HIV disease has been modified, and the need to treat HCV coinfection become a significant issue. Because of the poor response rate obtained by either interferon alone or interferon thrice weekly plus ribavirin, the combination of pegylated interferon and ribavirin will probably become the standard of care, although the clinicians should be aware of the overlapping toxicity of nucleoside analogues and ribavirin. Many selected categories of patients pose particular challenges to physicians treating HCV infection: nonresponders to interferon, cirrhotic patients, and patients infected with both HCV and HBV. Liver transplantation in HIV patients is currently under evaluation, but should become the rescue therapy for HIV patients with end stage liver disease.