In their introduction to this special issue, the editors mentioned that the commodification of labour is one important feature of capitalism. Hence, the reaction of the principal organizations that represent and defend labour needed to be explored. This article focuses on Belgian and German trade unions’ apprehensions of European integration during the 1970s and sheds lights on two major findings. First, trade unions’ perceptions of European integration were very clearly influenced by the condition and the evolution of capitalism. National trade unions observed that the transformations of capitalism could not be adequately addressed by national polities and industrial relations structures. Hence, trade unions heavily insisted on the necessity of political and trade unionist European cooperation. The latter is considered a necessary intermediary to allow labour to counterbalance the new forms of capital and to regain the influence it lost nationally. The second finding is that there existed a huge paradox between this enduring rhetoric of the necessity of European integration and the willingness of trade unions to give up some of their national prerogatives. The evolving forms of capitalism made it imperative to cooperate more at the supranational level but trade unions remained very much reluctant national institutions.