The article examines the scientific, political, and economic elements that permitted the birth of modern public health in Mexico under the Porfirio Díaz administration (1876-1910). Firstly, a portion of Mexican physicians were open to the discoveries of microbiology, immunology, and epidemiology. Secondly, the State's growing concentration of power in public health matters ran parallel to its concentration of disciplinary political power and enabled this new knowledge to be placed at the service of collective health problem prevention. Lastly, both imperialism and the Porfirian elite needed to protect their business interests. The article evaluates public health achievements and limitations during the Porfirian period, abruptly interrupted by the revolution begun in 1910.