Abstract In the relatively short history of Mercosur, the countries of the region have gone through wide macroeconomic fluctuations. Macroeconomic turbulence is not a novelty for Argentina, Brazil and their partners, but it has shown different features in recent years, particularly concerning the strength and nature of regional spillovers. Despite the asymmetries in size among the economies of the area and the low starting levels of trade, the rapid growth of intra-regional commerce until the last few years, and the feeling that there was a 'mercosur component' in the international demand for each country's assets, increased the visibility of regional macroeconomic interdependencies. However, there was little movement in establishing concrete forms of macroeconomic cooperation. These notes contain brief comments about the experience of Mercosur in macroeconomic matters, and some reflections about the possibilities for concerted regional actions. The paper quickly reviews aspects of the recent behavior of the economies of the area (focusing on Argentina and Brazil) and comments on the characteristics of macroeconomic interdependencies, and analyzes circumstances that have conditioned macroeconomic coordination within the region. Finally, it considers some policy options for regional cooperation in crisis situations.