The title of the essay refers to the famous statement in Foucaults introduction to his History of Madness where he writes that “we have to do justice to Freud“. The problem, however, is that Foucault’s philosophy does not seem to do justice to Freud. Foucault’s use of Freud is ambiguous: sometimes he uses him for purely instrumental purposes (when reconstructing the history of madness and sexuality), but sometimes—for anthropological purposes signaling Freud’s role in redefining our common humanity and particularly our relation to language, life and work. The author confronts Foucault’s ambiguous reading of Freud with the equally ambiguous reading of Foucault by Derrida. Derrida discusses Foucault twice. Once in the essay Cogito and The History of Madness in which Derrida takes on Foucault’s understanding of Descartes and his role in the exclusion of madness from the realm of reason. The second time—in his essay To Do Justice to Freud. Here Derrida disagrees with Foucault whether Freud managed to reestablish the body’s communication with reason which Descartes destroyed.