Background: The role of liver transplantation in patients positive for the hepatitis B surface antigen (HBsAg) is controversial because of the high rate of recurrent hepatitis B virus (HBV) infection. It has not been determined whether this risk is greater for certain patients and whether the administration of anti-hepatitis B surface antigen (anti-HBs) immune globulin is beneficial. Methods: We conducted a retrospective study at 17 European centers of 372 consecutive HBsAg-positive patients who underwent liver transplantation between 1977 and 1990. Recurrence of HBV infection was defined as the reappearance of HBsAg in serum. Results: For all 334 patients with follow-up data, the mean (±SE) three-year actuarial risk of recurrence of HBV was 50 ±3 percent. The risk was 67 ±4 percent among 163 patients with HBV-related cirrhosis, 32 ±5 percent among 110 patients with cirrhosis related to hepatitis delta virus, 40 ±16 percent among 14 patients with fulminant hepatitis delta infection, and 17 ±7 percent among 39 patients with fulminant HBV infection (P<0.001). Among the patients with HBV-related cirrhosis, the risk of HBV recurrence was greatest (83 ±6 percent) in those who were seropositive for HBV DNA at the time of transplantation and lowest (58 ±7 percent) in those with neither HBV DNA nor hepatitis B e antigen detectable in serum. With respect to the use of passive prophylaxis with anti-HBs immune globulin, the risk of HBV recurrence was 75 ±6 percent among the 67 patients given no immunoprophylaxis, 74 ±5 percent among the 83 treated for two months, and 36 ±4 percent among the 209 treated for six months or longer (P<0.001). In a multivariate analysis the predictors of a lower risk of HBV recurrence were the long-term administration of the immune globulin, hepatitis delta virus superinfection, and acute liver disease. For the entire study cohort, survival was 75 percent at one year and 63 percent at three years, but for those in whom HBV infection recurred, survival was 68 percent at one year and 44 percent at three years. Conclusions: In this retrospective study of HBsAg-positive patients, liver transplantation had better results in those who had fulminant hepatitis or delta virus superinfection. An absence of viral replication at the time of transplantation and long-term immunoprophylaxis were associated with a reduced risk of recurrent HBV infection and reduced mortality.