In Latin America, as elsewhere in the world, regional and subregional organizations have multiplied recently. Scholars tend to focus on the variety of regionalisms or their ever changing nature (post-liberal, post-hegemonic...). This study, through a political sociology of regionalism approach, examines Latin American regions and their actors and goes beyond the first set of questions. In this perspective, scrutinizing the regional General Secretaries of the sub-continent is particularly useful to understand how regional powers emerge. With a specific focus on the Southern Common Market (UNSUR), the Common Market of the South (MERCOSUR), the Andean Community of Nations (CAN) and the Central American Integration System (SICA), this research offers a more precise answer to the question of the configuration of power within Latin American regionalisms.