Lamivudine and famciclovir have expanded therapeutical options for HBV infection after liver transplantation. First studies confirm good antiviral effects of both, but at present the major problem seems to be a rapid resistance formation in immunosuppressed patients. Thirty-four adult patients with HBV recurrence despite passive immunoprophylaxis and seven with de novo infection after orthotopic liver transplantation (OLT) were treated with 100-150 mg lamivudine daily. Patients were either treated directly after infection (n = 14) or after breakthrough of viral replication during an initial famciclovir therapy (n = 27). All patients except two responded to treatment with a reduction of serum HBV-DNA of over 50%. Thirty-one patients (76%) turned HBV-DNA-negative during lamivudine therapy. Viral breakthrough was observed in 14 of these patients after 4-13 months of treatment. A total of 17 patients (40%) remained HBV-DNA-negative for more than 12 months. Only nine patients eliminated HBsAg, of which four had and an HDV coinfection. None of the HBeAg-positive patients converted to anti-HBe. Most patients showed a prompt and significant reduction of aspartate aminotransferase (ALAT) levels. No severe complications occurred. Therefore, a safe and effective therapy of HBV infection after transplantation is possible with lamivudine. Viral replication is suppressed even in patients who revealed breakthrough during famciclovir therapy. Resistance formation as a major drawback occurred in one third of the patients within the first year of treatment.