This dissertation explains "citizenship" as a practice and a tradition, rather than as a concept describing exclusive belonging to a political community. Immigration is commonly a condition of exclusion from citizenship in our contemporary world, as gender and slavery, have been in the past. Usually, immigrants have to comply with a subtractive model of citizenship and forgo their attachments to their homeland and mother language in order to be part of the new, dominant culture. This model is not smooth, and almost always entails hegemonic, or even violent practices of control from the state institutions either against the first, second, or even third generation. It is precisely from the point of view of immigrants that this exclusivity is challenged, and this work focuses on transnational citizenship and communication practices of indigenous Mexican immigrants in the United States as examples for the construction of a more cosmopolitan citizenship. Those practices offer a good example of how cosmopolitan engagement across nations is constructed from below, enriching instead of limiting the conception of citizenship. Using historical research, ethnography, and content analysis, I examine how transnational citizenship and communication practices among indigenous Mexicans living in California and organizing across borders, are transforming into cosmopolitan citizenship, engaging at least two nation-states along with international organizations into their daily lives. I study the case of one pan-ethnic and multi-site organization primarily composed of indigenous Mexicans from the state of Oaxaca named Indigenous Front of Binational Organizations (FIOB). A content analysis of two indigenous immigrant media is also included, reflecting this cosmopolitan engagement.