Ethical naturalism, the theory claiming that natural facts and especially facts concerning human nature play a justificatory role in ethics, is not very popular amongst moral philosophers. Especially in countries where Kant's influence is large, the charge of naturalistic fallacy is often made against it. The aim of this paper is to show that this charge misses the point: every ethical theory is at a certain level based on pure facts, natural or not, and natural facts concerning human nature are particularly suited for this role. The arguments in favour of ethical naturalism rely on a concept of human nature that includes basic desires related to ends we ought to pursue, as Aristotle and the Scholastics already saw long ago.