The article investigates Kantian cosmopolitanism, based on the philosophers works and his main commentators. The study chooses and highlights three central and specific themes: the evolution of the human species, the dilemma between sovereignty and cosmopolitanism, and the issue of hospitality. By casting light on these themes, the article attempts to fill in a gap in specialized literature from the fields of international relations and philosophy. Regarding the evolution of the human species, I emphasize the philosophers understanding of unsociable sociability a natural mechanism which provides the elementary basis for the advent of cosmopolitanism and perpetual peace. The dilemma between sovereignty and cosmopolitanism leads to the significant analysis of whether Kant has reflected upon or proposed transcending the paradigm of classical sovereignty. Finally, the discussion about hospitality becomes particularly relevant, and is scrutinized according to its juridical and ethical.