Liver transplantation for liver diseases related to hepatitis B virus (HBV) and hepatitis delta virus (HDV) remains problematic because of the risk of viral recurrence. We report here the long-term virological outcome of patients transplanted for HDV-related liver cirrhosis (HDV cirrhosis). From December 1984 to December 1990, 76 patients with HDV cirrhosis underwent liver transplantation. Before transplantation, all the patients were HBsAg-positive/anti-HDV positive, and all but one were HBV DNA-negative by dot blot hybridization. HDV RNA was detected by HDV RT-PCR and liver HDAg by fluorescent HDV Ab. After transplantation, all the patients except four received continuous long-term anti-HBs passive immunoprophylaxis. The actuarial 5-year survival was 88%. All patients who did not receive anti-HBs immunoprophylaxis remained HBsAg-positive and developed hepatitis. Among the 68 patients receiving antiHBs immunoprophylaxis with a minimum follow-up of 2 months, HBsAg reappeared in 7 (10.3%) after a mean of 17 months. These seven patients developed hepatitis, with simultaneous HBV and HDV replication; and four cleared later HBsAg. Patients without HBV reinfection were studied for HDV reinfection: liver HD Ag or serum HDV RNA were present in 88% of the patients during the first year, without developing hepatitis; however, they were no longer detectable after 2 years in 95% of the patients. In conclusion, liver transplantation for HDV cirrhosis gives good results, with a 5-year actuarial survival of 88%.(ABSTRACT TRUNCATED AT 250 WORDS)