The central aim of this dissertation is to examine the relationship between border zones, migration and national identities through the brasiguayos case. The dissertation will present the theoretical debate of these three dimensions in order to explain the political relations between Brazil and Paraguay which resulted in the Brazilian migration and colonization in eastern Paraguay, and generated new political subjects, the brasiguayos. Therefore, I will show that the border zone is more than an area of trade, presenting itself as the privileged space of social and cultural exchanges. My main point is that the border puts different national identities in touch and that this interaction creates new tensions with moments of conflict / integration between different peoples. Life along the border together with human mobility shows, moreover, how the idea of a nation tied to a state is tensioned. Therefore, the border highlights the need to think of new ways to constitute political identities, particularly in transnational contexts.