During the early modern period, unprecedented migration caused diseases to take hold in new locales, turning illness and the human body into battlegrounds for competing religious beliefs as well as the colonial agendas in which they were often ensnared. This interdisciplinary volume follows the contours of illness, epidemics, and cures in the early modern British and Spanish Empires as these were understood in religious terms. Each chapter of this volume centers on a key moment during this period of remarkable upheaval, including Jesuit co-optation of Indigenous knowledge in Peru, the Catholic Church’s dissemination of the smallpox vaccine across the Spanish Empire, Puritan collective fasting during smallpox outbreaks, and the practice of eating dirt as Obeah resistance among enslaved people in Jamaica. Throughout, the contributors explore how the porous geographical borders of the transatlantic world meant that medicine and religion were translated through and against each other, over and over again. Residing at the nexus between two largely discrete areas of inquiry, this collection provides significant insight into the numerous points of juncture between medicine and religion in the Atlantic world. In addition to the editor, the contributors to this volume include Matthew James Crawford, Crawford Gribben, Rana A. Hogarth, Philippa Koch, Allyson M. Poska, Catherine Reedy, and Rebecca Totaro.