This research questions the mechanisms and the form of associative commitment in consumer organisations in Valparaíso (Chile) and in Moselle (France). The point is to understand how the complex connexion between the will to form forces of opposition and the need to technicize their action so much that it pushes to professionalization acts on the commitment in institutionalized organisations. Thus, this study is at the meeting point of organizational studies, industrial sociology and the sociological studies of social movements.