The Orthodox Church from the very beginning of the Ecumenical Movement has been engaged into the healing of all sort of divisions and dissection. Many of the dissections divid Christians until today. In all the theological discussions Orthodox theologians emphasize that the Church is not simply an institution, but a mode of existence. The mystery of the Church even in its institutional dimension, is deeply bound to the being of man, to the being of the world and to the very being of God. The Church is also inseparable of its tradition and it cannot solve its present problems without constant referring to the decisive and formative centuries of the first millennium of Christianity. Therefore the contemporary involvement of the Orthodox Church into the Ecumenical Movement comes out from very nature of the ecclesial identity. Ecumenical activities of the Orthodox Church constitute the fulfillment of the wish of our Lord that all may be one.