Patients with chronic liver disease are at higher risk of hepatitis B (HB) virus infection before and after liver transplantation, and they commonly have a suboptimal immune response to HB vaccines. In this randomized trial, we compared the immunogenicity of primary vaccination with 2 doses of an experimental adjuvanted HB vaccine (adjuvant system 04 containing aluminium and monophosphoryl lipid A [HB-AS04] ) to that of 3 double doses of a licensed HB vaccine in 93 liver transplant candidates. Depending on the waiting list for liver transplantation, a booster dose of HB-AS04 or double booster dose of the licensed HB vaccine was given before or after surgery, at 6 to 12 months after initiation of the vaccination course. The percentage of subjects with seroprotective anti-HB surface antibody concentrations 1 month after booster was twice as high in the HB-AS04 group (60.0%), vs. patients in the comparator group (32.0%) (P ϭ 0.035). In subjects who did not undergo liver transplantation before administration of the booster, better immunogenicity results were obtained: 80% of subjects were seroprotected after HB-AS04 vaccination vs. 60% with the comparator (P ϭ 0.2302). Despite a slightly higher reactogenicity, the safety profile of the HB-AS04 vaccine was clinically acceptable. In conclusion, an improved antibody response was observed in liver transplant candidates with 3 doses of HB-AS04, as compared to 4 double doses of a comparator. Liver transplant candidates could benefit from the use of this experimental adjuvanted HB vaccine to further increase their protection against HB infection. Patients undergoing liver transplantation have an increased risk of exposure to hepatitis B (HB) virus, mainly due to transmission of the virus from the donor organ and, to a lesser extent, due to multiple transfusions of blood products. [1][2][3][4] To protect these patients against de novo HB infection acquired during or after Abbreviations: HB, hepatitis B; HBsAg, hepatitis B surface antigen; anti-HBs, antibody to hepatitis B surface antigen; AS04, adjuvant system 04 containing aluminium and monophosphoryl lipid A; GMC, geometric mean concentration; SAE, serious adverse event.