In the twentieth century, the Rockefeller Foundation was invited to extend its anti-hookworm program to Colombia. The foundation had two main motivations. First, to develop public health infrastructures and spread American ways of understanding health, and second, to ensure the stability of international commerce. This project explores how the priorities of the foundation and of Colombians were often at odds, and how these encounters shaped, or failed to reshape, the Rockefeller program in Colombia. Though the campaign operated nation-wide, this thesis focuses on the Colombian coffee community, government, and professional medical community. It explores how the Colombian medical community sought to deal with hookworm prior to the Rockefeller arrival, the period of direct American involvement in hookworm work, and last, the Colombian nationalization of the public health infrastructure following the foundation’s departure. Ultimately, the Rockefeller Foundation’s insistence on routine methods and inflexible attitude toward Colombia’s changing realities meant that Colombians exercising agency were viewed as obstacles to be overcome, rather than people with priorities to be engaged with meaningfully. The foundation’s failure to engage with many Colombians’ priorities resulted in a long and slow evolution whereby the Rockefeller agents in the country felt they only met lasting success in the 1930s, more than a decade after the start of the campaign.