This work analyses the development of a female political subject in Brazil and Argentina in the 1970s through the memory path and the notion of the political socialization of motherhood. For this purpose we compared two groups: the Mothers of the Square of May (Argentina) and the Women s Movement for Amnesty (Brazil). The historical differences in schooling and civic culture in the two countries, coupled with the intrinsic distinctions of each repressive system, gave rise to specific political opportunities. It was possible to observe throughout the documentary analysis of these two groups the construction - in a similar way, from the social representation of maternity, linked to the private sphere - a strategy of insertion in the public sphere. This strategy brought in its process the construction of a female political subject. In this way the struggle for memory within the perspective of the political socialization of motherhood becomes an element of the construction of a subject conscious of its capacity for action in the public sphere. In this perspective, after the re-democratization in the two countries, the trajectories of the Mothers of the Plaza de Mayo and the Women s Movement for Amnesty (MFPA) showed that what happened in Argentina was the construction of a social movement that brings together the defining elements of this concept, reaching its 40th anniversary in 2017. In Brazil, it was a social mobilization that, after the Amnesty Law in 1979, was fragmented into other movements or forms of action in the public sphere that became more dynamic in this country in the 1980s and 1990s.