Infection with HIV and HBV often coexist in the same patient as the two viruses share similar modes of transmission. Around 10% of HIV patients are co-infected with HBV. With early diagnosis of HIV infection and effective anti-retroviral treatment leading to improved survival of patients with HIV infection, Hepatitis B related liver disease is emerging as a significant health problem in this group of patients. Acute Hepatitis B tends to become chronic more often in HIV patients (80% vs 10% in HIV uninfected) indicating an immune dysfunction and defective clearance of the virus. Protection against HBV infection should be provided to HIV patients by effective use of Hepatitis B vaccine. Higher and frequent doses may be required in HIV patients as their immune response rates are poor. The response to treatment of CHB with Interferon-alpha in HIV patients is around 0-10%, much less than what is achieved in non-HIV patients. Considering the cost, adverse effects and the poor response with Interferon-alpha, there is lack of optimism vis-a-vis its use in HIV patients. The nucleoside analogue, Lamivudine, has shown promise in this group of patients. Lamivudine is useful in suppressing replication of both HIV and HBV. It has been found to be effective in suppressing HBV replication in 96% of HIV patients with chronic Hepatitis B infection. This was associated with clinical, biochemical and histological improvement in liver function. The dose of Lamivudine required in this special group is higher (300 mg/day), and the duration of treatment is long (until HBe sero-conversion and disappearance of HBV-DNA from blood). Besides, rebound viral replication on discontinuation of treatment and the development of YMDD mutants while on prolonged treatment are major concerns at the moment.