Treatment of HCV infection in HIV seropositives is becoming a management priority because of: the increasing HCV and stage liver disease mortality and the unfavourable impact of HCV infection on efficacy and toxicity of antiretroviral combination treatment. Treatment end points are: eradication of HCV or suppression of HCV replication in order to slow HCV disease progression and to increase efficacy and to reduce hepatotoxicity of antiretrovirals. Interferon as monotherapy and in combination with ribavirin induces eradication of HCV in respectively 17 and 28% and suppression of viral replication in 26 and 36% of treated HIV infected subjects. The impact of these drugs on HIV disease evolution and on antiretroviral treatment efficacy, toxicity and compliance needs to be established. Then the cost-effectiveness of anti HCV therapy in anti HIV infected patients still needs to be defined.