Results: The results of adding adefovir dipivoxil (ADV) 12 months to ongoing lamivudine therapy in 21 patients with clinical lamivudine resistance shows the adding ADV effectively suppressed the viral replication with reduction of medium serum HBV DNA - 4, 76log10copies / mL, virologic response (decline ofserum HBV DNA >2log10copies / mL) occurred in 80% of patients (12/15), among them 5 patients had late virologic response only after 9 months of treatment.