Post-transplant prevention of hepatitis B virus (HBV) infection is based on treatment with lamivudine and/or hepatitis B immune globulin (HBIG). However, optimum doses and duration for these drugs are not yet clear. We tested high doses of lamivudine (300 mg/day) in combination with low doses of HBIG (200-400 IU/2-4 weeks). Eighty patients who had post-transplant prophylaxis of lamivudine and HBIG were included in the study. Of those, 20 had hepatitis D virus co-infection and eight were HBV DNA-positive at the time of transplantation. Ten HBV DNA-positive patients were treated with lamivudine (150 mg/day) before transplantation; all were HBV DNA-negative after lamivudine treatment. All patients in the anhepatic phase were given 4000 IU of HBIG. Following this, 400 or 800 IU HBIG was administered intramuscularly daily for 5-10 days post-transplantation and 2-4 times weekly thereafter, according to serum titre of antibodies to hepatitis B surface antigen (anti-HBs). Lamivudine was maintained or initiated at the time of transplantation and was continued indefinitely. Median follow-up was 21 months (range 3-73 months). Recurrence of hepatitis B surface antigen (HBsAg)-positivity occurred in only three out of 78 (4%) patients; two of these three were HBV DNA-positive. Median anti-HBs titre at the final follow-up was 68 IU. Patient and graft survival was 85% at 1 year. In conclusion, a combination of lamivudine 300 mg/day and low-dose HBIG prevents post-transplantation recurrence of hepatitis B, even in the presence of viral replication in the pre-transplant period.