This paper explicates Descartes’ theory of intuition (intuitus). Departing from certain commentators, I argue that intuition, for Descartes, is a form of clear and distinct intellectual perception. Because it is clear and distinct, it is indubitable, infallible, and provides a grade of certain knowledge he calls ‘cognitio’. I pay special attention to why he treats intuition as a form of perception, and what he means when he says it is ‘clear and distinct’. Finally, I situate his view in relation to those of his Scholastic predecessors on one hand and current theories on the other. His view anticipates the contemporary ‘perceptual model of intuition’, though it is much bolder with its promise of certainty.