Dominus Iesus (Latin for "The Lord Jesus") is a declaration by the Congregation for the Doctrine of the Faith. It was approved in a Plenary meeting of the Congregation, and bears the signature of its then Prefect, Cardinal Joseph Ratzinger, now Pope Benedict XVI, and of its then Secretary, Archbishop Tarcisio Bertone, now Cardinal Secretary of State. The declaration was approved by Pope John Paul II and was published on August 6, 2000. It is subtitled "On the Unicity and Salvific Universality of Jesus Christ and the Church.
This document states that people outside of Christianity are "in a gravely deficient situation in comparison with those who, in the Church, have the fullness of the means of salvation", and that non-Catholic Christian communities had "defects."
Some non-Catholic groups have interpreted this as disparagement of their faiths while others have appreciated that the Church position does not deny the salvation of those officially separated from the Catholic Church.
Some actual text from the declaration...
The Christian faithful are therefore not permitted to imagine that the Church of Christ is nothing more than a collection divided, yet in some way one of Churches and ecclesial communities; nor are they free to hold that today the Church of Christ nowhere really exists, and must be considered only as a goal which all Churches and ecclesial communities must strive to reach. In fact, the elements of this already-given Church exist, joined together in their fullness in the Catholic Church and, without this fullness, in the other communities. Therefore, these separated Churches and communities as such, though we believe they suffer from defects, have by no means been deprived of significance and importance in the mystery of salvation. For the spirit of Christ has not refrained from using them as means of salvation which derive their efficacy from the very fullness of grace and truth entrusted to the Catholic Church.
The lack of unity among Christians is certainly a wound for the Church; not in the sense that she is deprived of her unity, but in that it hinders the complete fulfilment of her universality in history.