According to most interpreters, Aristotle explains death as the result of material processes of the body going against the nature of the living being. Yet, this description is incomplete, for it does not clarify the relationship between the process of decay and the teleological system in which it occurs: this makes it impossible to distinguish between natural and violent death. In this paper, I try to fill this gap by looking at his so-called ‘biological works’ and mainly at the De Juventute. I first introduce the specific concept of life at play in this treatise and prove its complementarity with the framework of the De Anima. Then, I illustrate in detail the process of dying and the reasons why a merely material description is insufficient to account for the distinction between natural and violent death. Finally, I show that for Aristotle natural death is a by-product of teleologically directed life activities: only against the background of this teleological structure is natural death fully explained in terms of essence and causes. To support this claim, I compare death to two analogous cases in Aristotle’s biology, namely dreams and the features of GA V.