This article deals with the problem of infant mortality in Santiago, Chile, and the development of pediatric medicine during the second half of the nineteenth century and the beginning of the twentieth century. Emphasis is placed on the specialists who contributed to organizing the knowledge and practices that structured their professional field. In order to pursue the objective and systematize this new medical field, our analysis suggests the decisive role of the establishment of the Faculty of Medicine and the appearance of coursework dedicated specifically to childhood diseases. Our research is based on various historical sources including the press, medical literature, thesis archives, and the Anuario Estadistico de la Republica de Chile [Statistical Yearbook of the Republic of Chile]. Likewise, the inauguration of children's hospitals expresses an institutional setting where physicians position their work, put scientific treatments into practice, and most importantly, they become spaces that allow for the reduction of infant mortality.