Resistance formation is a major problem in antiviral treatment of hepatitis B recurrence after liver transplantation. One possible therapeutic approach is an antiviral combination therapy with synergistic drugs. Four patients who were transplanted for chronic hepatitis B were analyzed retrospectively. All patients had reinfection of the graft and breakthrough of hepatitis B virus (HBV) during consecutive famciclovir and lamivudine monotherapy. Subsequently a combination therapy of lamivudine and interferon alpha 2a (3 times 3 million units weekly) was initiated. Addition of interferon markedly reduced viral replication rate in all patients. Three patients became HBV-DNA negative despite lamivudine resistance, but only two had a sustained response. No patient seroconverted to anti-HBe or lost HBsAg, but all patients showed a normalization of alanine aminotransferase and aspartate aminotransferase levels. No severe complications, and especially no rejection episodes occurred. Therefore lamivudine combined with interferon might be used for the therapy of hepatitis B reinfection after liver transplantation.