The Chaco War was a catastrophic conflict for Bolivia and Paraguay in several senses, having been especially transformative for the literature of the two countries, since during the period that followed, a new generation of artists, intellectuals and writers, who had in the conflict its main reference, had its artistic production marked by the generated transformations that created a period of great political and social instability in both Bolivia and Paraguay. The research proposes to understand the projects of nation elaborated through the social criticism and the representation of elements contained in the regional literature, especially in the two fictional works that revolve around this historical event: Hijo de Hombre and Sangre de Mestizos, respectively written by paraguayan Augusto Roa Bastos and the bolivian Augusto Céspedes. The Chaco was object of reflection in the narratives analyzed from various aspects, a projection screen of the nation, a protagonist in the narrative and perhaps the greater symbol of the injustices and oppression suffered by the population. The Chaco War defines the last physical borders of both Nation-states, and above all the imaginary frontiers of these nation projects. We will verify some fundamental elements in the proposals presented by the authors who sought to homogenize not only the nation they projected but also their national subjects.