The article explores the characteristics of infant mortality in Santiago during a historical period in which the demographic indicators reached very high figures turning the phenomenon into a medical and political issue. After commenting on historiographic data, it demonstrates the behavior of the infant population quantitatively, taking into account primary sources - from medicine, the press and civil records - and bibliography. It also exposes the motives employed by the elite to justify the children's deaths: materially, morally and culturally. The conclusion addresses the promulgation of the defenseless child law, the beginnings of knowledge on child health and the inauguration of the Child Hospital.