In the late nineteenth century, Mexico’s Superior Health Council devised a consistent and assertive international strategy around alignment with international scientific standards, the control of disease certification on Mexican soil by Mexican experts, transparent disease reporting, internationally demonstrated competence in campaigns against tropical disease, and participation in multilateral health agreements. The council came to command a central role in the regime of Porfirio Díaz (1877–1911), mainly because this international strategy enabled a successful defense of Mexican sovereignty. In the arena of public health, the council, led by Eduardo Licéaga, came close to realizing the Científicos’ dream of Mexican development “without U.S. investment.” This was largely because the council obtained independent access to European ideas and technologies prior to its engagement with the United States, which began in 1890 when the first Mexican delegation attended the annual meeting of the American Public Health Association (APHA). Through a persistent and creative diplomatic campaign, taking advantage of relationships cultivated through the APHA, Porfirio Díaz’s sanitary advisors persuaded many of their American counterparts that Mexican experts could be trusted partners in defending the health of the western hemisphere. The article describes the Atlantic world of Mexican medicine in the nineteenth century, the significance of public health within a context shaped by rising U.S. imperialism, the key role played by Licéaga, and Mexico’s participation in the APHA.