This dissertation explores U.S. commercial marketing's influence on HIV prevention programming in Tanzania, particularly the practice of social marketing. Social marketing NGOs in Tanzania uphold the goal of creating commercial markets in condoms and promoting HIV prevention behaviors among the public through commercial advertising. Their aim is to address health inequalities among urban low income communities through application of new theories regarding "the social" nature of markets to make privatized access to health goods equitable and sustainable. This dissertation analyzes and historicizes social marketing naturalizations of interventions in human decision-making and economies based on the idea that humans are driven to pursue pleasures which undermine their ability to make rational choices in the interest of health. By drawing on the accounts of individuals - including members of Islamic-based health NGOs, Tanzanian entrepreneurs, and individuals in impoverished neighborhoods targeted by health programs - this work describes the politics and stakes of social marketing interventions, including unanticipated economic and health marginalization. Each of these groups drew from moral understandings of the imbrication of economic, political, and social life to critique the privatization of public health. This dissertation maps these controversies not only as debates about public health and political economy grounded in terms of a critique of private property, but as entailing epistemological and ethical claims about health, markets, and human nature.