We often speak of an action of one person as imposing a risk of some kind on another person. In this chapter I argue that, contrary to what has sometimes been claimed, the imposition of a risk of, say, physical harm – or, in a different formulation, the deprivation of a chance of avoiding an adverse physical outcome – is not a form of harm in itself. One of the implications of the argument I shall present is that the concept of imposing risk is a complex and sometimes elusive one. On first examination one might think, for example, that the character and the magnitude of the risk that one person has imposed on another are matters that can be settled simply by appealing to ordinary facts or to scientific knowledge, but I argue that this is not so. For moral purposes, at least, we can only determine what risk A has imposed on B by making certain assumptions about the knowledge and beliefs that an actor in the position of A ought to have possessed at the time of acting, and the question of which assumptions are appropriate requires us to look to moral considerations. It follows that, in the moral context, at least, the concept of risk imposition is itself a moral notion. A more general theme of the chapter concerns the importance of what I shall call morally determined epistemic perspectives in all moral and legal discourse about risk. In the final section of the chapter I refine the claim that risk is not harm in itself, and I also offer a preliminary discussion of some more general questions that this claim suggests about the relationships that hold among the concepts of risk, harm, interests, and rights.