ARISTOTLE ON PURSUIT AND AVOIDANCE. Pleasure and pain play an essential role in Aristotle’s conception of the goal‑directed activities of animals and human beings, since they trigger the reactions of pursuit or avoidance, and hence the entire behavior. The present paper inquires into Aristotle’s analysis of this phenomenon on the basis of De Anima III , chapter 7 and De Motu Animalium, chapters 6‑7‑8. The crucial move in this analysis is the definition of pleasure and pain given in both treatises : “To feel pleasure or pain is to actualize through the sensitive mean towards what is good or bad, as such”. The paper examines the meaning of this definition and shows how it connects and agrees with the explanation of the principles of the physical motions of animals in the De Motu Animalium.