The article is devoted to the analysis of class actions in Argentina and Brazil. Within the article, the author compares the institution with a similar institution in the United States. It is noted that the origin of this type of lawsuits in the United States can be explained by borrowing from the old English law of equity. In Argentina impossible to find a comprehensive procedural mechanism for resolving conflicts involving large groups of people. Lack of appropriate procedural mechanism at the federal level is a particular problem, as the amendment to the Civil Procedure Code, which established the lawsuit in the exercise of the collective rights with constitutional recognition in this country, as well as some of the substantive rights that cannot be designated as a «collective». In Brazil, the use of legal rights of consumers can search for both an individual and a collective basis. A special feature is that collective redress is possible only when the defendant has violated at least one of the three main categories of collective rights. The first category is the «common law». It includes the rights belonging to an indefinite group of persons who are related to each other factual circumstances. The second category is called «collective rights». They differ from the common rights that belong to the group, category or class of persons, by virtue of the basic relations. Highlights the third category of collective rights, designated as «individual homogeneous», but generalized for the purposes of the trial. 

Keywords: civil litigation; collective (class) actions; foreign civil process.