Vatican Doctrine of Faith Declaration
An excerpt…
17. Therefore, there exists a single Church of Christ, which subsists in the Catholic Church, governed by the Successor of Peter and by the Bishops in communion with him. The Churches which, while not existing in perfect communion with the (Roman) Catholic Church, remain united to her by means of the closest bonds, that is, by apostolic succession and a valid Eucharist, are true particular Churches. Therefore, the Church of Christ is present and operative also in these Churches, even though they lack full communion with the (Roman) Catholic Church…
From the Vatican, August 6, 2000