This thesis explores the development of Puerto Rican public health institutions and policy from 1898 to 1917. I ground the research in the major constitutional legislative actions (Foraker Act of 1900, Jones Act of 1917) taken by the United States to highlight both the key political moments in the colonial relationship between the metropole and colony and the accompanying ramifications for the public health institutions on the island. Case studies of epidemic disease outbreaks - smallpox, hookworm disease, and bubonic plague - facilitate an assessment of how political partisanship, international philanthropic groups, and interest group politicking affected the execution of campaigns responding to these diseases. I show that the circulation of personnel, philosophies, materials, and technologies within the American sphere of influence alone resulted in a sanitary imperialism that was a unique and cosmopolitan amalgamation of the latest medical and public health science of the day. I contend that the annexation and administration of Puerto Rico was above all haphazard in the early years of the twentieth century. The narrative that emerges from other historians who argue that highly specific themes or debates were the central issue does not fit the archival record. Such single-factor explanations as race, gender, sexuality, religion, or economic expansion mask the importance of highly particular factors on the ground. This thesis demonstrates that an understanding of the Puerto Rican context requires a more nuanced and even-handed approach than previous literature has provided. Health policy and institution building from 1898 to 1917 is a story of the continuous attempt to disentangle public health from partisan politicking. In large part, public health and disease campaigns were conceptualized as a means of enhancing commercial ties with the international community and improving the economic outlook of the island.