The Church has always affirmed that baptism is «the sacrament of faith by which men, illuminated by the grace of the Holy Spirit, respond to the Gospel of Christ ». In Scripture baptism appears as «always linked to faith » and to conversion, and both aspects (conversion and faith) are constitutive of the very sacrament of baptism itself. The realisation of these aspects in subjects who receive baptism (especially children) raises quite a few questions. Because, if on the one hand it is impossible that in children baptised shortly after birth that there should be personal faith and conversion, on the other hand it is questionable if baptism is ever or can ever come to be the «foundation» and the «door» to all of Christian-life. Because of this we have a triple objective: 1. To present a brief history of the relationship between faith and conversion in the first centuries and in the church of Vatican II and since. 2. To state some principles and theological questions which spring from it. 3. To propose some pastoral suggestions.