Naturalistic philosophy attempts to inform itself with the most accepted scientific theories available. Evolutionary ethics, as a naturalistic philosophy of morality, must therefore inform itself with widely accepted theories available about evolution. In this paper we analyze the implications of Darwinism in both the descriptive and prescriptive domains of ethics. By giving a theory of normative justification we offer an account of how to move from descriptive ethics to prescriptive ethics. This account works as a filter that avoids committing what some call “the naturalistic fallacy” but at the same time allows making a move from ‘is' to ‘ought'. We first focus in the negative implications, i.e. what does not follow from Darwinism: In the descriptive level, some evolutionary approaches to ethics are dismissed, since their teleological view of evolution is incompatible with Darwinism. In the normative level, the theories derived from a teleological view, like (the wrongly called) “Social Darwinism” and Waddington's ethical-political view, are also discarded. Then we focus on the positive implications, i.e. what we can conclude from Darwinism on ethics: In the descriptive level, models of moral psychology are extracted from Darwinian explanations and supported by experimental studies. We conclude that positive implications in the prescriptive level are too risky and point out several issues that have to be further discussed, like the problems posed by Darwinism to Moral Realism and Moral Intuitionism.