This paper interrogates the parameters of atheistic existential ethics. Specifically, it evaluates the ethical implications of the concepts of freedom and subjectivity in the select works of French existential philosophers, namely; Jean Paul Sartre, Simone De Beauvoir and Albert Camus. The paper primarily choose the trio based on their atheistic inclinations with the key objective of examining the justifiability of the foundation of their existential morality. With subjectivity at its core and possibility always on the horizon, these existentialists have sought to explain how we create values. Such values have no absolute meaning but rather emerge from our own subjective projects and concerns and not from God or any ultimate Being. The paper argues that atheistic existentialism has not been able to account for the moral dimension of human life, and thus, have no basis for an ethical theory if they deny that humans are bound God’s commands. It suggests that the idea of God's non-existence casts a serious doubt on the possibility of any notion of moral foundationalism. The basic features of existentialism found in their works seem, at least superficially, to undermine the possibility of ethics which they profess. The paper maintains that if God does not exist, we will not be provided with any absolute values or commands that could either approve or disapprove our actions. It concludes that a self created being has no moral foundation and no compelling moral force since his existence cannot be founded on no higher or ultimate Being.