Morbidity and mortality from co-morbid hepatitis B (HBV) and hepatitis C (HCV) infection in HIV co-infected patients are increasing; hence, the management of HIV and HBV or HCV co-infected individuals is now one of the most challenging clinical management issues. Less than 10% of all HIV-infected patients show markers of chronic HBV infection. Hepatitis B in HIV co-infected patients is characterized by high levels of HBV replication and a high risk for cirrhosis. Treatment of HBV with lamivudine (3TC) remains the best treatment option at this time. Initial results of studies of adefovir or tenofovir, however, demonstrate good antiretroviral efficacy, even in patients with 3TC-resistant HBV. In Europe, it is estimated that approximately 30% of HIV-infected individuals are co-infected with HCV. HIV accelerates HCV liver disease especially when HIV-associated immune deficiency progresses. Within 10-15 years of initial HCV infection, 15-25% of patients who are co-infected with HIV develop cirrhosis compared with 2-6% of patients without HIV infection. With the introduction of pegylated interferon in combination with ribavirin, promising treatment options have become available for HIV/HCV co-infected patients leading to early virological response rates of approximately 50%. The high number of HIV/HCV and HIV/HBV co-infections, as well as the much more unfavorable course of HBV and HCV in these patients, underlines the need to establish treatment strategies for HBV and HCV in HIV co-infected individuals.