This dissertation examines the modernization of aspects of Cuba’s public health programs through the influence of the Rockefeller Foundation. As a result of its sponsorship of projects, the Rockefeller Foundation contributed to the spread of modernizing practices and policies from 1913 through 1945. An evaluation of medical modernization remains an important chapter in the study of post-colonial development. Current research has often portrayed public health modernization efforts as unidirectional with the United States imposing its ideas and practices onto developing nations. By examining institutional records, personal correspondence, and reports, this dissertation provides a more nuanced analysis of the relationship between Cuba and the United States during this period. This dissertation also argues that efforts to modernize Cuban public health were in fact the result of bilateral cooperation between Cubans and the United States. This study evaluates efforts made by scientists, researchers, and professionals to expand educational programs, to implement public health structures, and to develop new techniques for treating disease. During its occupations of Cuba at the turn of the century, the United States advanced public health programs and infrastructure. This work was later continued under the Cuban Republic with the support of private US interests, the Rockefeller Foundation. This dissertation addresses a significant gap in existing research by providing a different lens with which to view public health modernization in Cuba. Despite the past and ongoing presence of United States government interests in Cuba, the Rockefeller Foundation only pursued projects in Cuba after obtaining permission by the Cuban government. In one instance, Cuban physicians persistently requested for the involvement of the Foundation to forward their own aims. Both the Foundation and the Cuban government were interested in adopting successful programs established elsewhere and in using scientific findings from surrounding regions to advance research in Cuba. Instability in the newly formed Cuban Republic undermined these projects and prevented them from achieving their primary aims. Although these public health modernization plans made strong gains in some areas, at times they fell short in their primary agendas.