Currently, there are no effective antiviral treatments to cure HBV infection in patients with chronic hepatitis B. Five drugs have been approved for the treatment of chronic hepatitis B at present: conventional interferon (IFN) alpha, lamivudine, adefovir dipivoxil, pegylated IFN alpha and recently entecavir. Conventional IFN alpha monotherapy has a narrow range of efficacy. Lamivudine, is relatively cheaper, better tolerated, and has been shown to be effective in patients with both hepatitis B e antigen (HBeAg)-positive and -negative chronic hepatitis B. However, virologic response to lamivudine is not as durable as that occurred spontaneously or induced by IFN treatment. In addition, prolonged lamivudine treatment is commonly associated with the emergence of drug-resistance HBV mutants accompanied by the development of breakthrough hepatitis. Adefovir is potent and has been approved for the treatment of chronic hepatitis B in several countries, but is nephrotoxic at daily doses higher than 10 mg and is still not available widely. Entecavir, a carbocyclic deoxyguanosine analog, which is active against both lamivudine- and adefovir dipivoxil-resistant HBV, is the most potent anti-HBV agent ever discovered,11 however, its long-term efficacy remains to be evaluated. Pegylated IFN alpha has recently been shown to be superior to conventional IFN alpha and lamivudine, and has also been approved for the treatment of chronic hepatitis B. Overall, satisfactory virologic and serologic responses could be achieved using pegylated IFN alpha alone in around 30-44% of these patients. Nevertheless, better treatment options are still needed for the remaining >50% non-responders.