The present text analyzes the changes in the structure of the media system in four South American countries during the first decade of the 21st century: Argentina, Brazil, Chile and Uruguay. The general premise is that the current levels of concentration in media markets have accelerated during the first decade of the 21st century as a consequence of the historical processes which have taken place in these countries, although each has different origins and effects in each of these national cases. Increased concentration, the media convergence with telecommunications and the Internet, the growing financial dependence of the sector, the foreign acquisition of a significant amount of their property at the hands of multinational firms and the crisis of the current regulatory frameworks are the main frameworks for understanding the transformation of the media in the Southern Cone of Latin America. The processes of change identified to describe and analyze the evolution of Brazilian, Argentine, Chilean and Uruguayan media in recent years could not have been achieved without the collaboration of different governments and the radical transformations in the management and ownership patterns of these media.
