Intravenous hepatitis B immunoglobulin (HBIG) is a human plasma-derived purified gammaglobulin (IgG) that has proven efficacy and dose-dependent response in the prevention of hepatitis B virus (HBV) recurrence after liver transplantation. It is also indicated for postexposure prophylaxis after contact with blood or body fluids of serum hepatitis B surface antigen (HBsAg)-positive carriers and in prevention of mother-to-child (vertical) transmission. The exact mechanism of passive immunization is unknown; HBIG may block HBV entry and binding to hepatocytes, neutralize circulating HBV and target HBV-infected cells through an antibody-mediated immune response. The drug is well tolerated and common side effects include fever, chills and arthralgias that are usually mild and transient. This article summarizes the main indications and the recommendations for use of intravenous HBIG, as well as the usage of intramuscular HBIG in the liver transplant setting.