The outcome of renal transplantation is adversely affected by hepatitis B virus infection. We retrospectively analyzed data of 1,251 renal transplant recipients, 20 of whom were hepatitis B surface antigen positive and hepatitis B virus DNA negative at the time of renal transplantation. Hepatitis B virus reactivation was seen in 14 of the 20 patients at a mean time of 16.3 ± 7.1 months after transplantation. All patients with hepatitis B virus reactivation after transplantation were treated with lamivudine, biochemical, and serologic response was achieved in 13 of 14 patients at a mean time of 7.0 ± 1.1 months. Seven of 13 patients experienced a breakthrough at a mean time of 9.2 ± 6.2 months. Three of the 20 patients died at a mean time of 57.0 ± 38.5 months after transplantation. Our data demonstrated that chronic immunosuppression is associated with a significantly high risk of hepatitis B virus reactivation in renal transplant recipients and hepatitis B reactivation does not increase the likelyhood of graft rejection or patient mortality after renal transplantation.