This paper positions Sartre's conception of freedom within his analysis of Being and Nothingness all of which have their basis in human consciousness. I intend to show how consciousness determines what constitutes being, non-Being, negation, phenomenon and freedom. On the whole, I will show that Sartre's phenomenological and ontological analysis of Being and Nothingness are intended to argue the point that consciousness determines what manifest as Being or as Nothingness. How human consciousness authentically does this constitutes the realm of freedom for Sartre.