Résumé : BACKGROUND: Patients who have been exposed to the hepatitis B virus (HBV) and who were able to clear the hepatitis B surface antigen from the serum and to develop anti-hepatitis B surface antigen (anti-HBs) antibodies are not considered at risk for HBV reactivation after solid organ transplantation. METHODS AND RESULTS: We, however, observed three solid organ transplant recipients who demonstrated clinically significant HBV reactivation after transplantation. All patients presented normal liver enzymes and serological stigmates of healed HBV infection at the time of transplantation, as indicated by the absence of hepatitis B surface antigen and the presence of anti-HBs and anti-hepatitis B core antibodies in the serum. Patient 1, a renal transplant recipient, presented HBV reactivation 3 years after transplantation and developed chronic HBV hepatitis. Patient 2 developed HBV reactivation 7 months after a second cadaveric renal graft and died of cirrhosis four and a half years after transplantation. Patient 3, a heart-lung transplant recipient, developed HBV reactivation within months after transplantation, but died of unrelated causes. HBV reactivation in the presence of anti-HBs antibodies has been previously reported in other settings of immunosuppression, mainly in patients with acquired immunodeficiency syndrome and after bone marrow transplantation, and may lead to fatal liver disease. Data from our renal transplant recipients suggest that the incidence of HBV reactivation among patients with anti-HBs and anti-hepatitis B core antibodies is about 5%. CONCLUSIONS: Transplant physicians should be aware of the risk of HBV reactivation in patients presenting with healed HBV infection before transplantation.