New antiviral agents are currently being developed to treat patients with chronic hepatitis B. Both pegylated interferon alfa-2a and entecavir are now approved for the treatment of hepatitis B while telbivudine, tenofovir, emtricitabine, and pegylated interferon alfa-2b are in clinical development. Successive advances have resulted in more profound suppression of hepatitis B replication, a reduction in breakthrough resistance, and an increase in the frequency of attainment of virologic, serologic, biochemical, and histologic clinical endpoints.