Abstract: Objective To observe the effect of lamivudine and adefovir combination therapy on patients with chronic hepatitis B. Methods 11 patients tolerated lamivudine switched to adefovir，6 tolerated to adefovir switched to lamivudine，and 28 tolerated lamivudine and 9 tolerated adefovir switched to lamivudine and adefovir combination therapy. Results At the end of 48 weeks therapy，the serum HBV DNA negative rate（76%）and ALT normalization rate（92%）in combination group were much higher than in adefovir（45%，73%）or lamivudine（50%，83%）groups. Conclusion The combination of lamivudine and adefovir therapy is an alternative option in hepatitis B patients tolerated to adefovir or lamivudine.

Key words: Hepatitis B, Lamivudine, Adefovir, Mutation