Abstract: This article summarizes the most relevant aspects of the most advanced integration process in South America: The Common Market of the South or MERCOSUR. It is described from origins of MERCOSUR, its organizational structure, its economic-commercial and political evolution and its legal-institutional dimension to its external relations and participation in multilateral negotiations. It also describes the progress related to the process of social and citizen integration and the measures that MERCOSUR has adopted to face the challenges of the coronavirus pandemic.

Keywords: Integration law; MERCOSUR; Common Market; South America; integration process.