This article interprets Sartre's ethical reflections as leading to a negativistic ethics, that is to say an ethics that denies the possibility of conceiving a positive ideal that has to be attained, and therefore limits itself to the criticising of the negative in the existing world as the only way left for ethics. After a brief introduction into negativism, the article sets out the negativism of Being and Nothingness and the metaethical dilemma that the ontological work poses for a conception (...) of a traditional, positive ethics, which Sartre apparently tried to undertake in his Notebooks for an Ethics . Instead of speaking of a failure of Sartre's attempts to found a traditional ethics, the article shows how already in the Notebooks Sartre is on the way to establishing a conception of an ethics that can be called negativistic, and finally how the late Sartre attains, on the basis of the socio-ontological insights of his Critique of Dialectical Reason , a foundation for a genuinely negativistic ethics which he drafted in his 1964 Rome Lectures. (shrink)