This chapter provides a political sociology of the European Trade Union Confederation (ETUC), studying the resources held by the confederation and its leaders. It shows that the ETUC detains significant material and institutional resources, but that these are highly dependent on the European Commission. Moreover, these resources are highly sectoral, linked to the field of European social policies, and are only mobilized by a small number of European trade unionists involved in the confederation’s activities. Finally, the sociology of ETUC leaders underlines their partial Europeanization: they have acquired resources tailored to representing interests in Brussels, but remain above all trade union professionals.