Chronic hepatitis B is a major cause of mortality and morbidity in Hong Kong and most Southeast Asian countries. The efficacy interferon-alfa (IFN-alfa) or lamivudine monotherapy is far from satisfactory with approximately 20% sustained viral response. Extended use of lamivudine is associated with the emergence of drug resistance mutants. As interferon is an immune modulator and lamivudine directly suppresses viral replication, it is therefore logical to combine the 2 drugs for more efficient viral clearance.