The basic theme of this text is the comparison between two discourses on the architechtural modern, which were especially relevant in Brazil and Argentina from the 20s to the 40s. These positions are well represented by Lucio Costa and Alberto Prebisch. The text considers the confrontation between two different forms of reading the European discourse -with emphasis on the interpretation given by Le Corbusier- and the values and demands present in the Argentinian and Brazilian sociocultural and political structures; starting on them those discourses were read and appropriated. The wole resultant representations that contributed with their singularity to the feedback of the ideological node the modern as a problem, are comparatively analyzed through the texts which these two arquitects wrote during the period previosly marked.