The announcement of the First National Plan for Agrarian Reform in May 1985 led to the mobilization of Brazil's rural dwellers. Small producers, landless peasants and agricultural workers all claimed their rights of access to the land. This article addresses women's participation in this movement, both at the institutional level and in non institutionalized groupings. Using the results of field work carried out after a popular « invasion » in the state of Rio de Janeiro, the authors explore the roles of women in the organization of the encampments and in the consolidation of formal ownership of land. The emergence of a strong autonomous movement among rural women from southern Brazil, calling for the recognition of women as agriculturalists in their own right, is also examined.