Chronic hepatitis B and C are life-threatening diseases, treated with variable success. Peginterferon-α is one of the standard therapies for chronic hepatitis B as well as C. To prevent the development of resistant viruses, combination treatment is preferable to monotherapy. Therefore, in chronic hepatitis B virus peginterferon-α combined with nucleoside inhibitors is used. The treatment of chronic hepatitis C virus with a combination of peginterferon-α and ribavirine can be improved by new protease inhibitors.