Jürgen Habermas’s theory of communicative action has provided the inspiration for a school of Critical International Relations Theory which looks to communication as a source of praxis, and therefore a means of emancipation. This article argues that Critical International Relations Theorists have been too ready to accept Habermas’s claims about the emancipatory power of communication. In particular, it is not clear that a Habermasian Critical International Relations Theory can address the concerns of more sophisticated materialists — not least those of Habermas’s predecessors in the Frankfurt School of Critical Theory. One of the most original of these predecessors, Theodor Adorno, argued that the pursuit of communication between subjects would result in the betrayal of Critical Theory to the requirements of instrumental reason. The article suggests that similar concerns are apparent in International Relations: in Marxian criticisms of the turn to communication; in accusations of ‘anthropocentrism’ aimed at post-positivists by Critical Realists; and in Andrew Linklater’s emphasis on the common human capacity to experience and recognize bodily suffering. Adorno’s Critical Theory points to the need for a reorientation of Critical International Relations Theory towards an account of praxis which draws upon the experiences and needs of corporeal, vulnerable human beings who are part of a material world. In this way, critical International Relations theorists can carry forward the critique of global socio-political forces which the majority of the world’s inhabitants experience as an arbitrary constraint.