At the time of the foundation of the World Council of Churches in 1948 there were no regional ecumenical organizations yet. The first to come into being was the East Asia Christian Conference, in 1957. It was followed in 1959 by the Conference of European Churches (CEC). At the early stage of this new development in the ecumenical movement, the leadership of the WCC voiced some concern that it would lead to fragmentation and weakening of the oneness of the movement. However, the creation of regionalized ecumenical instruments reflected the felt need of the churches for a place where they could deal with the specific issues of their region, and make their voice heard at the regional level. Regional ecumenical organizations also provide a context for the churches to express and celebrate their common regional identity, culturally, historically and politically.
In 1963, the African churches founded the All Africa Conference of Churches (AACC), and in 1966 the churches in the Pacific established the Pacific Conference of Churches (PCC). The Caribbean Conference of Churches (CCC) was formed in 1973. That same year the East Asia Christian Conference became the Christian Conference of Asia (CCA). In 1974, the churches of the Middle East brought into being the Middle East Council of Churches (MECC). And in 1982 the churches in Latin America created the Latin American Council of Churches (CLAI). The only region where there is no such body is North America.
Although the regional ecumenical organizations (REOs as they are being called) share a common identity and constitute a distinctive group within the one ecumenical movement, they differ in approach, priorities, working style, and structure, according to the particularities of each region. The different designations of "conference" and "council" also reflect nuances in their self-understand-ing. In two of them, the Christian Conference of Asia and the Pacific Conference of Churches, national councils of churches are full members along with the churches. The Caribbean Conference of Churches has a category of associate membership for national councils of churches; the All Africa Conference of Churches, the Conference of European Churches and the Latin American Council of Churches have a similar associate status for councils and other organizations. The Middle East Council of Churches is shaped according to the specific model of "families of churches".
In three of the regional bodies the Catholic Church is a full member: in the Caribbean Conference of Churches as founding member, in the Pacific Conference of Churches since 1976 and 1991, and in the Middle East Council of Churches since 1990. The Christian Conference of Asia works closely with the Federation of Asian Bishops' Conferences, with which it has formed an Asian Ecumenical Committee. Similarly, the Conference of European Churches and the Council of European Bishops' Conferences cooperate in various programmes and have jointly organized European Ecumenical Assemblies. The Latin American Council of Churches is in dialogue with the Latin American Episcopal Conference.
In the early 1980s, the regional ecumenical organizations began to develop inter-regional cooperation. The general secretaries of the organizations started meeting regularly, to share information and discuss common concerns. The World Council of Churches joined this process. In 1992, the REOs and the WCC formulated and agreed on a set of "guiding principles for relationships and cooperation". Since then, an "REOs and WCC General Secretaries Group" meets annually. It should be underlined that the regional ecumenical organizations are entirely autonomous bodies, which in no way depend structurally or otherwise on the WCC. The WCC has formally acknowledged the REOs in its Rules as "essential partners in the ecumenical enterprise". This partnership is reflected in the intensive programme cooperation between WCC teams and REOs, in a variety of ways, according to the nature of the programmes and the regional priorities.