The Roman Catholic Church (including all its component particular Churches, whether Latin or Eastern) practices closed communion. Christians that do not share its theology of the Eucharist (such as those who follow Protestant teaching on the matter) are absolutely excluded. Those who do personally share Catholic belief in the Eucharist are permitted to receive the sacrament in accordance with norms established by the episcopal conference and on condition that "the person be unable to have recourse for the sacrament to a minister of his or her own Church or ecclesial Community, ask for the sacrament of his or her own initiative, manifest Catholic faith in the sacrament and be properly disposed" (Directory for the Application of Principles and Norms on Ecumenism, 131). In the case of members of the Eastern Churches, which have the same belief in the Eucharist, the conditions are only that they "ask for the sacrament of their own free will and are properly disposed", but the Directory warns in the same context (125) that "due consideration should be given to the discipline of the Eastern Churches for their own faithful and any suggestion of proselytism should be avoided."
The Eastern Orthodox Church, comprising 14 or 15 autocephalous Orthodox hierarchical churches, is another closed-communion church. Thus, a member of the Russian Orthodox Church attending the Divine Liturgy in a Greek Orthodox Church will be allowed to receive communion and vice versa, but a Protestant or a Roman Catholic attending a Greek Orthodox liturgy will be excluded from communion. In either case, non-Christians are also excluded.
Among Baptist churches, closed communion is the practice of restricting communion (or The Lord's Supper) to only those who hold membership in the local church that is observing the ordinance. Thus, members from other churches, even other Baptist churches, will be excluded from participating in the communion service. This viewpoint is usually, though not exclusively, associated with Landmark ecclesiology.
Confessional Lutherans, or those such as are found in the Lutheran Church - Missouri Synod, the Wisconsin Evangelical Lutheran Synod, and the Evangelical Lutheran Synod practice closed communion. Failing to do so is condemned by confessional Lutherans as the sin of unionism. The Apostolic Christian Church, Church of God in Christ, Mennonite, Amish, some churches in the Reformed tradition and Primitive Baptists also practice closed communion. Other groups that practice closed communion are Jehovah's Witnesses.
The term close communion normally means the same thing as closed communion. However, some make a distinction, so the terms can be a source of confusion.
The most prominent distinction (which in some circles may be called "cracked communion") is one where a person of the "same faith and practice" (generally meaning the same or a similar denomination) may participate in the service whether or not they are a member of the local congregation, but a member of another denomination may not. For example, a Southern Baptist church practicing close communion might allow another Southern Baptist church member, or a Missionary Baptist church member, to participate, but might exclude a Catholic, on the basis that the Baptist members are of the "same faith and practice" but that the Catholic is not.
The Reformed Presbyterian Church of Australia allows communion to those who can assent to the first three terms of its Covenant of Church Membership, and discuss this with the elders ahead of time. They don't appear to distinguish the term "close communion" from "closed communion", though.
The earliest use of close communion comes from a mistranslation of the Lutheran theologian Franz August Otto Pieper's Christian Dogmatics. The term has since spread, although both the first edition and later translations corrected the error to "closed communion."
Corporate responsibility is another argument often used in favour of closed communion. The Heidelberg Catechism, for example, says that those who "by confession and life, declare themselves unbelieving and ungodly" are not to be admitted to the Lord's Supper, for then "the covenant of God would be profaned, and his wrath kindled against the whole congregation." Church leaders are obliged to do all they can to ensure that this does not happen, and hence "exclude such persons... till they show amendment of life," (Q & A 82).
If a Roman Catholic marries a Syriac Orthodox Christian in a Syriac Orthodox church, the priests in both churches may allow the Roman Catholic to receive communion from the Orthodox priest at the wedding. The Holy See recognizes the validity of Eastern Orthodox sacraments and poses conditions under which Catholics may receive them. A Catholic priest would deny permission for a Catholic to receive communion in a Protestant church, since according to Catholic teaching the Eucharist in Protestant Churches is considered invalid, on the grounds that the minister was not ordained by a bishop in a line of valid succession from the apostles (referred to as Apostolic Succession), although the Church of England argues that it is part of the Apostolic Succession for this very reason. The Roman Catholic Church also rejects the apostolic succession of the Anglican Communion, a position that the Church of England disputed in Saepius Officio. Some hold that a Catholic priest could give communion to a Protestant marrying a Catholic, even outside the conditions mentioned above, provided the Catholic understanding of the Eucharist is not in any way contradicted.
Many Scottish Protestant churches used to give tokens to members passing a religious test prior to the day of communion, then required the token for entry. Some US and other churches also used communion tokens.