The primary goal of hepatitis B prevention programs is reduction of chronic hepatitis B virus (HBV) infection and HBV-related chronic liver disease. Although donor screening, risk-reduction counseling and services, and effective infection control practices can reduce or eliminate the potential risk for HBV transmission, immunization is by far the single most effective prevention measure. Worldwide, the integration of hepatitis B vaccine into existing childhood vaccination schedules has the greatest likelihood of long-term success. However, by 2000, only 116 of 215 countries had such a policy, representing 31% of the global birth cohort. In addition, efforts must be strengthened to vaccinate older adolescents and adults with high-risk behaviors or occupations in countries where most HBV transmission and the morbidity associated with acute hepatitis B occur among persons in these age groups. Although continued immunization of successive birth cohorts should achieve the eventual elimination of HBV transmission, this will not occur for decades without successful vaccination of adults at increased risk for infection.