In March 2003, the Southern Common Market (Mercosur) celebrated its twelfth anniversary. In twelve years, the bloc went from a substantially restricted trade structure to a practically free-trade area, with additional efforts in establishing a customs union and progressing toward a common market. Despite these advances, the integration process has experienced setbacks as the result of such different economic phenomena as the Asian financial crisis, Brazil's currency devaluation and, later, economic uncertainty in Argentina. Setbacks to the integration process create credibility issues and could jeopardize the future of the process. This paper discusses the current level of economic integration of Mercosur, the speed of the process, and the resulting mixed level of different stages of economic integration. It also discusses the main achievements in the last twelve years, identifies the shortcomings as well as the opportunities and challenges facing the bloc in the near future.