The Aptian Stage along the Eastern Brazilian Margin (Santos to Camamu-Almada basins) was analysed in 28 wells drilled by PETROBRAS, including 750 meters of cores. The results were compared to those of core samples analyses of DSDP 511 well (Malvinas Plateau). The Aptian Stage along the Eastern Margin can be subdivided into two main packages. The lower one is characterized by continental sedimentation under rift tectonics. Only sporadic marine incursions have been recognized in this package and this scarcity is related to the existence of very restricted water circulation conditions at this time in the southern portion of the South Atlantic Ocean (Malvinas-DSDP 511 well area), precluding significant northward movement of water in the Brazilian coast. The Upper Aptian Stage package was deposited under more quiet and stable tectonic conditions, in a sag basin. This package can be subdivided into two portions with distinct lithologic characteristics. The lower one is dominated by fluvio-alluvial sediments covering most of the proximal areas of all the marginal basins. Distal sediments of this unit were, however, deposited under shallow marine conditions. This first ingression is related to an increase of marine water circulation in Southern South Atlantic (Malvinas area). At the end of the Aptian a strong period of aridity associated with a major barrier represented by the Sao Paulo Volcanic Ridge and the Florianopolis High, led to the deposition of a very thick marine evaporitic package ("Ibura Event").