Studies concerning Augustine’s teaching on infant baptism usually emphasize his insistence on the necessity of baptism for the salvation of infants, and/or the damnation of infants who die without baptism. Far less has been said about the damnation of infants who die with baptism. Nevertheless, Augustine categorically denies salvation to those who are baptized and remain outside the Church, even though he insists that they can have the true sacrament, and he makes no exception for infants. Furthermore, Augustine occasionally preaches that the benefit of the sacrament is jeopardized even for infants within the Catholic church, when their parents or baptismal sponsors do not believe rightly. By the end of 413, however, he begins to teach clearly that all baptized infants within the Church are saved. By examining in greater detail the sources of Augustine’s affirmation of the certainty of the salvation of baptized infants within the Church, it becomes clear that this teaching—which today is taken for granted—was not universally or even necessarily commonly accepted. Rather, it stood in opposition to a variety of doubts and denials, which came from all quarters. Indeed, Augustine seems to have been unique, in that he provided a well-developed rationale, and—subsequently—a previously unknown certainty for the salvation of baptized infants within the Church.