We deal with the meaning of the ethical question in Foucault's thought. We find first that he makes two criticisms: (1) of the subject as a category, and (2) of the subject as the outcome of relations of power and knowledge. Such criticisms relate to the ethical question as its conditions of possibility. Then, we study the genealogy of this new dimension of ethics, analyzing its different historical configurations. This work shows that it is necessary to bring about an aesthetics of existence. This is tackled starting from a reworking of the pars construens of Foucault's philosophy, whose central aspect turns about ethics conceived as care for freedom. El artículo aborda el sentido de la cuestión ética dentro del pensamiento de Foucault....