The aim of the paper is to show the role and meaning of Descartes’s philosophy in the context of Heidegger’s way of philosophizing, focusing on his metaphysics of subjectivity. According to Heidegger the latter is marked by a transformation in understanding the being of existence. By this he meant the fact, that the in representation of being is determined by the subject. What really is and is valid as existing, is only the object in the re-presentation of the re-presenting person. Heidegger argues that the modern history of being, from its understanding as re-presentation (Descartes) up to the will to power (Nietzsche) can be conceived as the history of metaphysics of subjectivity. For Heidegger Descartes’s metaphysics is an instantiation of thinking which is limited by the existence without recurring to the most fundamental aspect, namely its being.