The text is a presentation of how the relationship between Brazil and Argentina in the last five decades has affected the perception and constitution of the political-strategic Marinas in both countries. From a position of rivalry and competition, they opted to the attempts of integration and cooperation in various sectors, including the military-naval one. In this sense, certain significant issues are considered in the implementation of the Mercosur and of confidence-building measures along with other neighbors in the South American subcontinent, from the perspective of analysts, civilians and Brazilian and Argentinian official mariners justifying the advances and limits of the cooperation. And so, It is taken into account the establishment of the defense policy bases and some consequences for the military-naval formation in both countries.
Regional Cooperation; Political and Strategic Thought; The Argentinian Navy; Brazilian Navy