Although the best treatment choice for chronic hepatitis B is not clarified yet, certain therapeutic concepts could be derived from the experience of treating patients with chronic hepatitis C or human immunodeficiency virus (HIV) infection. A major advancement in treating hepatitis C or HIV infection has been the development of combination therapy. Whether the combination therapy using Peg-IFN alfa-2a plus ETV can achieve a long-term beneficial effect against ETV alone is not clarified. A prior single-arm pilot study suggested that similar combination therapy may be beneficial in patients with chronic hepatitis B. In this proposal, we thus hypothesize that the efficacy by using combination therapy with pegylated IFN alfa-2a plus ETV is superior to that by using ETV alone in that Peg-IFN may restore host immunity against HBV and prolonged ETV can maximize viral suppression.