The grave challenge posed by the recent pandemic of acquired immunodeficiency syndrome is not the first time mankind has faced such a threat. Useful lessons may be drawn from the successful global Smallpox Eradication Program and applied to the current campaign in the areas of surveillance, strategy, operations, and evaluation. The most important epidemiologic characteristic of this new infection is the unprecedented observation that virtually all asymptomatic infected persons are infectious and will remain so indefinitely. In combatting this infection we should concentrate our efforts in the United States on preventing transmission from the estimated 1.5 million persons who are already infected. We must make the best use we can of all the tools we already have: public information, health education, counseling and serologic testing of persons at high risk, treatment and prevention of intravenous drug abuse, and serologic screening of organ and tissue donors. Adequate confidentiality of test results needs to be secured in order to promote voluntary testing as an important means of achieving behavorial change among persons who are most likely to have been exposed to the infections. Persons whose sexual or drug abuse behavior puts them at higher risk of infection are the highest priority target group. They should be sought at every opportunity, whether seen in public clinics or private practice, and advised to be tested. In order to focus on preventing sexual, parenteral, and perinatal transmission of the virus we must avoid numerous potential distractions and irrelevant issues: we don't have time for them.