Nephrotoxicity is one of the adverse effects of lamivudine and dosage of lamivudine has to be reduced if patients' renal function is insufficiency. Telbivudine may improve glomerular filtration rate. This study is to see whether renal function is improved when Lamivudine is replaced by telbivudine in liver transplantation patients.

Liver transplantation is the only effective treatment for the patients with liver failure. Hepatitis B-related liver cirrhosis is the major indication to have liver transplantation in Taiwan. After liver transplantation, prophylaxis of hepatitis B recurrence will be performed by anti-hepatitis B immunoglobulin and anti-viral agents. Currently, lamivudine is the drug the investigators choose to prevent HBV recurrence for many years because it is safe for long-term use. However, nephrotoxicity is one of the adverse effects of lamivudine and dosage of lamivudine has to be reduced if patients' renal function is insufficiency. Recently, the studies on chronic hepatitis B patients showed improvement of glomerular filtration rate for those receiving telbivudine treatment. In this study, the investigators will include our post-transplant HBV patients who have stable liver function, receive lamivudine for prophylaxis of recurrent hepatitis B, and have renal dysfunction in stage II-IV. The patients will be randomized to receive telbivudine or lamivudine continuously at 1:1 ratio. Renal function will be examined at 6 months interval to determine whether renal function is improved. The achievement will determine whether telbivudine is better than lamivudine for the HBV patients with renal dysfunction.

Inclusion Criteria:

1. Sign inform consent
2. Age is not less than 16 years old.
3. Post liver transplantation patient for HBV-related indication.
4. Chronic hepatitis B transplant patients who are treated by lamivudine for not less than 6 months.
5. eGRF stage 2-4 patients (15\