Eradication is the permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed. To date, the only infectious disease that has been eradicated is smallpox. Poliomyelitis is targeted for eradication by the year 2000, and the eradication initiative is well under way, with the Western Hemisphere certified as being polio-free and more than one year having passed since polio cases occurred in the Western Pacific Region of the World Health Organization. A review of the technical feasibility of eradicating other diseases preventable by vaccines currently licensed for civilian use in the United States indicates that measles, hepatitis B, mumps, rubella, and possibly disease caused by Haemophilus influenzae type b are potential candidates. From a practical point of view, measles seems most likely to be the next target. Global capacity to undertake eradication is limited, and care must be taken to ensure that a potential measles eradication effort does not impede achievement of polio eradication. Even in the absence of eradication, major improvements in control are both feasible and necessary with existing vaccines. New and improved vaccines may give further possibilities of eradication in the future. Eradication represents the ultimate in sustainability and social justice.