The theme of this book is social security and non-contributory social protection, and its focus is to present the Brazilian and Argentine social protection models through the historical background and recent changes in the formation of social security in Brazil and Argentina. The research data was collected through bibliographic research in books, theses, dissertations and scientific journals, and also from documentary sources through the official websites of the governments of the two countries. In addition, data was collected via questionnaire with Brazilian and Argentinean researchers in the area of Social Sciences, Political Science and Social Work.