Purified from the plasma of hepatitis B carriers, hepatitis B surface antigen particles have been used in a vaccine to prevent hepatitis B. This plasma-derived vaccine is immunogenic, protective, and has an excellent safety record. Indications and strategies for preexposure and postexposure prophylaxis are reviewed. In addition, novel approaches to hepatitis B vaccine development are being pursued and will provide the basis for the next generation of vaccines. Early progress has also been made toward a hepatitis A vaccine, but clinical availability is not imminent.