This dissertation analyses the dynamics of the popular initiative in the legislative process at the 1988 National Constituent Assembly and in the 1988 Republic Constitution. In order to achieve that goal, this work starts from the main theoretical bases of the democratic field, placing the popular initiative in the legislative process in the context of participatory democracy. After the theoretical exposition, the research is based on the investigation of the popular amendments in the constituent process from 1987 - 1988, presenting the theme with a brief reflection about the pre-constituent phase, passing through the reconstruction of the debates and legislative decisions which enabled the usage of the popular initiative in the legislative process, until reaching the analysis of the popular proposals presented to the National Constituent Assembly s Systematizing Commission. Next, this paper discusses the investigation of the constituent debates that enabled the inclusion of the popular initiative in the legislative process in the Constitution s final text. Hence, this dissertation catalogues and analyses the experiences of popular initiative in the legislative process presented to the Deputies Chamber and deals with the inventory of its occurrences at the legislative assemblies in the states of Minas Gerais, São Paulo, Paraná, Espírito Santo and at the Legislative Chamber of the Federal District. Finally, this dissertation will, briefly, analyze the amendment proposals to the Constitution tending to reduce the demands for the proposal of legislation projects originated from popular initiative and, in a wider manner, the performance of the Commission for Participative Legislation of the Deputies Chamber.