The article deals with ecumenism and the most important examples of its “institutionalisation”. It is stated that ecumenism implies the doctrine (idea), universal inter-church movement and the proclaimed goal of achieving Christian unity. It possesses at least theological, sociological and political determinants. The World Council of Churches is a universal inter-church forum for dialogue and cooperation that lacks clear ecclesiological identity. However, it is getting the characteristics of a typical international political movement. The Conference of European Churches is a similar European organization. The Parliament of World Religions tends to found and promote “global ethics” in order to accomplish pacifistic goals in the world.