Close foreign policy cooperation among a limited number of EU member states is generally looked upon with suspicion as it is associated with ‘directoires’ of large member states. The central argument of this paper is that, under certain conditions, the specialisation and division of labour among the member states can strengthen both the effectiveness and legitimacy of the foreign policy of the EU. This paper proposes the establishment of a system of small, specialised EU core groups that focus on particular foreign policy issues. An EU core group consists of (representatives of) the high representative, the Commission and the presidency and of a limited number of EU member states that are both willing and able to devote extra efforts and resources to a specific foreign policy matter. A system of EU core groups can help to alleviate some major problems of EU foreign policy: the cleavage between large and middle-sized or small member states, the predominance of uncommon interests, a lack of cooperation and vertical consistency, and the growing irrelevance of the Council in an EU with 25 or more member states.