It is unclear whether heart donors positive for hepatitis B core antibodies (anti-HBc) can transfer hepatitis B virus (HBV) infection to immunosuppressed heart recipients, or whether passive transfer of anti-HBc simulates a hepatitis B infection. Therefore, we performed a case-controlled study in 46 heart recipients who all tested negative for hepatitis B antigen (HbsAg), antiHBc, and hepatitis B surface antibodies before heart transplantation. Twenty-three patients (group 1) received hearts from anti-HBc-positive donors, while 23 other patients (group 2) received hearts from anti-HBc-negative donors. After heart transplantation, anti-HBc were present in 65.0% of blood samples among group 1 and 47.8% of the blood samples among group 2 (P > .05). HbsAg was undetectable in blood samples of all patients of both study groups. The immunoglobulin preparation that we regularly use for immune suppression immediately after heart transplantation contained a relatively high concentration of anti-Hbc antibodies. The nearly identical presence of anti-HBc in both study groups indicated that passive transfer via immunoglobulin preparations rather than HBV infection is the cause for the anti-HBc detected in heart recipients. Since only a small volume of blood is transferred with the donor heart, it seems to be rather unlikely that the donor heart might be the source of anti-HBc. In summary, we observed no evidence for HBV infection in those heart recipients who received organs from anti-HBc-positive donors. Moreover, our data demonstrated that the presence of anti-HBc in heart recipients frequently occurs but does not necessarily indicate a preceding HBV infection.