BACKGROUND/AIMS: The aim of this study was to evaluate whether the regimen consisted of lamivudine and one-week HBIg for HBV prophylaxis after liver transplantation is as effective as long-term therapy of high dose HBIg. METHODS: Sixty-one patients with HBV infection were randomly divided into two groups: HBIg group of 31 patients and combination group of 30 patients. In the HBIg group, HBIg was given according to the standard dosing schedule. In the combination group, lamivudine was given indefinitely from at least 4 weeks before transplantation, and 10,000 IU of HBIg was given during anhepatic phase and 6 consecutive days. RESULTS: The two groups were not different in HBeAg and HBV DNA positivity. In the HBIg group, the median follow-up of 20 long-term survivors was 12.7 months (range: 4.0 - 48.2) and that of 23 survivors in the combination group was 22.3 months (4.2 - 42.2). Hepatitis B recurred in a patient of the HBIg group and 2 of the combination group. The recurrence-free survival rate of long-term survivors was 66.7% (95% C.I., 39.5% - 93.9%) in the HBIg group and 76.0% (58.6% - 93.4%) in the combination group after 40 months. CONCLUSIONS: The combined therapy of lamivudine and one-week HBIg has an effect equivalent to long-term therapy of high dose HBIg in HBV prophylaxis after liver transplantation at a much lower cost.