In this article I wish to discuss the problem of self-knowledge in Sartre’s early philosophy with regard to its consequences within the field of ethics. I shall not try to cover all aspects of self-knowledge in Being and Nothingness since all of the major doctrines expounded in that work concerning consciousness, identity, freedom and knowledge have implications for self-knowledge. I would be content if I could draw attention to aspects of Sartre’s thought which are interestingly different from other moral philosophies as well as from certain empirical conclusions it would seem natural to draw from Sartre’s own ontology in the sphere of moral psychology.