Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5-and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P ؍ NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200-99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P ؍ .0003). options. The introduction of high doses of hepatitis B immune globulins (HBIG) or of lamivudine (LAM) as post-LT mono-prophylaxis has reduced the risk of hepatitis B recurrence to a variable cumulative rate ranging between 10% and 50%. During prophylaxis with LAM or HBIG a strict correlation between hepatitis recurrence and hepatitis B virus (HBV) DNA load at the time of surgery has been found, which is related to the emergence of viral mutants that are unresponsive to therapy, such as surface antigen (HBsAg) mutants and tyrosine-methionine-aspartate-aspartate (YMDD)-mutants. 1 -5 Moreover, neither HBV recurrence nor graft failure have been observed in patients with HBV DNA undetectable by polymerase chain reaction at the time of surgery and treated with HBIG. 6 The risk of hepatitis B recurrence can be reduced to less than 10% by using LAM before and after LT, in association with HBIG. 7 -13 Moreover, although LAM therapy before transplantation can improve liver function and decrease mortality, 14 long-term antiviral therapy can select YMDD mutants whose management needs the use of alternative drugs, such as adefovir dipivoxil (ADV), to reduce HBV recurrence after LT. 15 -19 However, a variety of issues still remain controversial. In particular, doubts remain as to what virological status has to be achieved in patients undergoing LT and which HBV DNA assays have to be performed. This study analyzes 177 HBsAg carriers who underwent transplantation in a single center between 1990 and 2002 with the aim of evaluating the prognostic role of the HBV DNA viral load at the time of surgery on the risk of hepati...