The article deals with Adorno’s conception of exteriority as an example of the philosophical materialism. In the first part, the concepts of exteriority and interiority are defined and the methodological differences between a materialistic and an idealistic approach are depicted. A materialistic approach can be combined with the efforts of the masters of suspicion: Marx, Nietzsche, Freud. Adorno can be regarded as one of the major masters of suspicion in the twentieth century. In the next part, three basic models of exteriority and interiority elaborated by Adorno are presented. In the first model, the external and internal nature and the principle of self-preservation are introduced. It shows the relationship between the exteriority and interiority of thinking. The second model deals with Adorno’s concept of the non-identical, which can be conceived as an exteriority in relation to the conceptual systems that produce it. The third model displays historical conditions of conceptual thinking as related to the establishment of the domination in history (class-ordered society).