The purpose of this study was to evaluate the criteria of social classification in Brazil and the changes they went through form the beginning of the Real Plan as well as through decrease in inflation rates. The study is documental in nature since it draws extensively from the pertinent literature. It also deals with associated concepts such as social and economic criteria, demographic segmentation, social classes and epidemiology, poverty, income distribution and the effect of new technologies. The study shows the variety of approaches to social class measurement and the risks of targeting errors in an economy in which large economic inequalities prevail. In this sense, the study tries to understand the adopted social classes and its later subdivisions.