A comparative, descriptive and analytical study of mental health systems in Brazil and Argentina, considering some of the developments and structures of implementation of the anti-asylum trend in the countries analysed and studying these factors in conjunction with regulations issued by international organisations in favour of this change in trend, from 1975 until the present-time. In this regard, the principal reference used in this study is the Caracas Declaration of 14 November 1990, created at the Regional Conference for the Restructuring of Psychiatric Care in Latin America, and signed by both countries, each therein committing to the restructuring of their respective mental health systems in accordance with the recommendations stipulated in the document. The analysis has three strands: a study of the published legislation, a study of existing practice in the Field, and a case study of two pioneering experiments of implementation of anti-asylum logic carried out simultaneously in each of the two countries. The study uses as theoretical reference the hypotheses of the Institutionalization Movement and the work of Michel Foucault, as well as the extensive ideology supporting the development of the anti-asylum trend: Basaglia, Tosquelles, Oury, Castel, and others.