The Southern Common Market (MERCOSUR) as integration process, has been the subject of countless studies by specialized doctrine, on its organic institutions and regulations, of commercial and economic aspects, as well as of the other “dimensions” that have been added since its founding act in March 1991, to the present. In this paper, the proposal is to analyze the integration of the point of view of the countries that make it up as “regional integration scheme” of “intergovernmental” character or nature, since its incorporation in both “State Party” or “States Parties” (founding), and mainly engaging in this process of integration of the so-called “Associated States”, which ultimately are the two established procedures for participation in the regional scheme according to MERCOSUR rules.