Because of complex interactions between HIV, hepatitis B virus (HBV), immune system and antiretrovirals, treatment of HBV infection in HIV population should consider both viruses. In co-infected patients with no indication of antiretrovirals, drugs with dual activity against HBV and HIV are not recommended to avoid development of HIV resistance (lamivudine, emtricitabine, entecavir, tenofovir disoproxil fumarate). Adefovir dipivoxil or pegylated interferon may be used. Telbivudine may have a role in combination with adefovir dipivoxil in this situation. In patients with an indication of antiretroviral therapy, regimens should include tenofovir in association with lamivudine or emtricitabine. In patients who had developed HBV lamivudine (or emtricitabine) resistance addition of tenofovir to antiretroviral regimen including maintenance of lamivudine or emtricitabine is the preferred choice.