Although Michel Foucault did not specifically write on confession, he often referred to it, especially in the last years of his life when thinking about the self. He devotes a large part of his lectures at the Collège de France and his seminars in various countries to confession. Foucault, in the Will to Knowledge, the first volume of the History of Sexuality, speaks of confession when he traces how sexuality is multiplied as the regime of truth. Confession as the form of knowledge-power in the relationship of sexuality to confession appears in a series of transformations. The sexuality, through its inheritance from Christianity has transformed confession into another form. How this happened is put forward by a distinction between erotic art and sexual science. Foucault, in the last years of his life will focus on confession as the knowledge of the self rather than on confession as the form of knowledge-power. The confession as it emerges in the techniques of the self is, in a sense, as well complementary of the genealogy of sexuality as different from it. For some, this situation is described as a return to the subject and even to a weakness. Foucault, however, deals with the techniques of the self to understand how truth procedures work. In order to reveal this connection, it is necessary to think about the confession as it appears both in the field of sexuality and in the techniques of the self.