It is widely held that compensating donors for their plasma will exploit them. But expression of this concern is rarely accompanied by supporting argument. When discussions of donor exploitation actually do move beyond mere expressions of concern to offer arguments they rarely engage with the relevant philosophical literature. As a result, they are often based on an underinformed view of what exploitation is. This chapter develops and defends an account of exploitation that both capture standard intuitions as to when a transaction is exploitative and also explains why these transactions are wrongful. This account of exploitation is developed independently on concerns about the exploitation or otherwise of plasma donors. But not only will it establish that current compensation practices do not exploit plasma donors it also establishes that the prohibition of donor compensation will exploit some donors.