How does the process of medicalization take place when historians examine not reformers, but institutions and populations subject to medical reforms in a specific country? Traditional histories of medicine have focused on the steps “great medical men” took to adapt European medical sciences to the Mexican context. While valuable, this approach assumes that the process of medicalization concludes with the creation of modern medical institutions. But here is just where it starts. In the mid-19th century, most of Mexico’s population was mestizo, agrarian, Catholic, and illiterate. White and literate criollos lived in a few major urban centers from where they governed the country or administered their large states. Part of the latter group, doctors sought to modernize medical institutions by adopting enlightened science. The details of how different groups responded to this process of medicalization are just beginning to be studied. Papers in this panel examine the tensions between science, religion, and state-building in the medicalization of Mexican society in the 19th and 20th centuries at several levels: parishioners and their congregations confronting smallpox vaccination, patients and doctors at the maternity ward of an urban hospital, a “folk saint” and its devotees in the US-Mexican border, doctors questioning the epistemological, moral, and gender implications of the termination of pregnancy, and homeopathic practitioners challenging the straightforward adoption of Bacteriology and Physiology in medical programs and practice. The picture that emerges is one of negotiations where medical traditions merged into plural approaches to healing.