Exclusivism

Exclusivism from a Christian perspective is the view that a person must know of Jesus Christ and consciously decide to believe and follow him in order to achieve salvation.

This view can be teased out in a variety of ways, such as claiming that a person must be baptized into a particular tradition or church in order to be saved, or make a conscious decision to "invite Jesus into your heart" or make Jesus one's "Lord and savior." This view usually entails a belief in "one true faith" or "one true church."

On this view, a person who has rejected the Christian message or has never had the opportunity to hear it has no hope of achieving salvation.

Many Christians in the Reformed tradition hold to an exclusivist position in virtue of a belief in predestination, which can be found articulated in the Westminster Confession of Faith (1646).

See also:
The Wikipedia entry on "Religious Exclusivism" (section on Christianity)
An article on "Christian Exclusivism"