Full communion

Full communion is completeness of that relationship between Christian individuals and groups which is known as communion. Implying a unity unbroken by heresy or schism, it requires agreement on essential doctrine and practice and a willingness to have close relations. Absolute uniformity in theology and usage is not necessary: provided that this essential unity is maintained, different understandings and emphases are seen as mutually enriching.

Partial communion exists where elements of Christian faith are held in common, but complete unity on essentials is lacking. For example, the Catholic Church sees itself as in partial communion with Protestants, and as in much closer, but still incomplete, communion with the Eastern Orthodox Churches (see Catechism of the Catholic Church, 838).

The word "communion" is used not only of the bond uniting Christian individuals and groups, but also of groupings of Churches that explicitly recognize the existence between them of this bond in its full form. Examples are the Anglican Communion and the Porvoo Communion.

Full communion (in different senses) exists between:
 * 1) The particular Churches that form the Roman Catholic Church, which sees itself as one Church, not as a grouping on the lines of those just mentioned (the 28 May 1992 Letter to the Bishops of the Catholic Church on some aspects of the Church understood as Communion, 9 declares: "The universal Church cannot be conceived as the sum of the particular Churches, or as a federation of particular Churches. It is not the result of the communion of the Churches, but, in its essential mystery, it is a reality ontologically and temporally prior to every individual particular Church.") This includes Latin Catholic Church, the Maronite Catholic Church, the Syrian Catholic Church, etc.
 * 2) The (approximately 16) autocephalous Churches that likewise form the one Eastern Orthodox Church
 * 3) The Coptic, Armenian Orthodox, Eritrean Orthodox, Jacobite, Indian Orthodox and Ethiopian Orthodox Tewahedo Churches (called "Oriental Orthodox" Churches)
 * 4) The Anglican Communion, the Old Catholic Church, the Mar Thoma Syrian Church of India, and the Philippine Independent Church.
 * 5) The Churches of the Porvoo Communion
 * 6) The Episcopal Church in the United States of America and the Evangelical Lutheran Church in America
 * 7) The Anglican Church of Canada and the Evangelical Lutheran Church in Canada
 * 8) The Evangelical Lutheran Church in America and the Moravian Church, as well as the ELCA with the Presbyterian Church USA, the Reformed Church in America, and the United Church of Christ, and the Moravians with the United Methodist Church.
 * 9) The United Methodist Church is currently working diligently toward full communion with both the Evangelical Lutheran Church in America and the Episcopal Church in the United States of America.
 * 10) The Church of England is currently working diligently toward full communion with the Methodist Church of Great Britain.
 * 11) Many of the Independent Catholic Churches are working diligently toward full communion with each other and with the Old-Catholic Union of Utrecht.

In the case of the last-mentioned groupings (from no. 4 on), full communion means little more than an arrangement for:
 * mutual recognition of members
 * common celebration of the Lord's Supper/Holy Communion/Eucharist
 * mutual recognition of ordained ministers
 * mutual recognition of sacraments
 * a common commitment to mission.

Full communion means much more for the first-mentioned. The constituent particular Churches of the Catholic Church see each of them as the embodiment of the whole unique Catholic Church in a specific area. Similarly, each of the Eastern Orthodox Churches is viewed as a particular embodiment of the one Orthodox Church. This oneness is understood differently in the latter-mentioned.

The first-mentioned also see sharing the Eucharist as the sign of full communion, the goal to which those striving for unity look forward. Others view this sacrament rather as a means of achieving unity by fostering fellowship (see open communion).