Este artículo tiene por finalidad analizar una de las expresiones mas descarnadas de la chilenización de Tarapacá después de los sucesos del 21 de diciembre de 1907: las ligas patrióticas. Grupos paramilitares, ilegales pero aceptados por la sociedad civil y el Estado chilenos, organizados con el propósito de expulsar a la población peruana residente previo al anunciado plebiscito de Tacna, contribuyendo con ello a terminar con el periodo internacionalista y pluriétnico de la región, e iniciar el periodo nacionalista y de región frontera. ------------------------- This paper aims at analyzing one of the most frightful expressions of the “Chileanization process “in Tarapacá after the events that took place on December 21 st, 1907. There were some paramilitary associations named Patriotic Leagues. They were illegal, however these leagues were accepted by civil society and by the Chilean Government. These groups had been organized with the purpose of forcing the resident Peruvian population out of this region before the already announced Tacna Plebiscite, trying with this fact to put an end to the mul ti- ethinc and internationalist period which was being lived in this part of the continent, and starting the nationalist and region-frontiered period.