The present text seeks to go into the ecumenical dimension of theology, which ought to be present in all theological work, but which also centres very particularly on certain theological questions. ‘Ecumenical theology’ is thus presented as a means of reflecting theologically containing specific elements of a hermeneutic, methodological and spiritual order, though basically within a framework of systematic theology. The article begins with a brief analysis of forms of relating and of confessional discussion which preceded what we now know as ‘ecumenical theology’ – a diachronic, historical perspective, not forgetting its current relevance. It goes on to draw attention, secondly, to some of the principal features that, in terms of spiritual attitude, methodological choices and a hermeneutical perspective, characterise an ecumenical theology. There follows, as a third point, a specific reflection on ecumenical theology as a hermeneutic of unity in diversity. This hermeneutical task, which takes in not only texts, but a whole set of experiential elements of transmission and witness of faith, is characterised by two fundamental orientations: a hermeneutic of unity in search of the truth and a hermeneutic capable of comprehending and integrating difference. As a singular case of the concretisation of an ecumenical theology and, at the same time, as a place for the verification of its difficulties in methodological and hermeneutical terms, a fourth section tackles the task of the reception of the results of the theological dialogue. In this context, on the one hand, the importance of reception is underlined, alongside its conditions and demands, and, on the other, attention is drawn to certain priority tasks for theological reflection, with a view to the future. From this follows, by way of conclusion, an analysis of the core question of the objective of the unity to be created. Here emerges the urgency of clarifying in ecumenical dialogue the indeclinable demands of the unity to be created, which cannot occur without a deeper and more open consideration of the question of the presence of Christ’s Church in history.