ON OCT 4, 1978, the Secretary of the Department of Health, Education, and Welfare, Joseph A. Califano, Jr, announced, "We are launching an effort that seeks to free the United States from measles by October 1, 1982" (statement made in Washington, DC, Oct 4, 1978). In announcing this initiative, the secretary noted the "remarkable progress made in controlling measles in the past 15 years" that made possible such an attempt to "eliminate indigenous cases of measles in this country." The purpose of this article is to describe the epidemiologic and operational history behind this initiative, to present its scientific rationale, and to summarize the major tactics viewed as essential to its successful execution. Background Measles has had severe impact in the United States. Outbreaks were reported as early as 1635; a major epidemic occurred in the colonies in the period 1713 to 1715. In 1772, it was reported that 800