Página intencionalmente deixada em branco. ABSTRACT VERONEZ, F. A. Effectiveness of environmental impact assessment on Espírito Santo State (Brazil). 2018. 214 f. Tese (Doutorado) -Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, 2018.This thesis is investigating the Environmental Impact Assessment (EIA) system which is implemented in Espírito Santo State (Brazil). I aim to fill a gap in existing critical literature, by bringing attention to empirical evidence in a long-term study of EIA practice. The effectiveness of the EIA system was analyzed by applying an analytical framework focusing on four dimensions: procedural, substantive, transitive and normative effectiveness. As for the methods used during the analysis, they are: survey, documentary analysis, case studies, expert consultation and interviews. Using a qualitative-quantitative approach, the research was supported by 47 decision-making processes, analyzing the Environmental Impact Statements (EIS) and documents submitted in a period of ten years (from 2007 to 2016). The results indicate that the EIA system proved to be punctually effective, although the negative results prevail. Elements of effectiveness and evidence of EIA influence on the projects with favorable results to the environment were identified, as well as elements of learning from the EIA practice that signal to the perspective of improvement of the EIA system. However, the results indicate weakness related to the absence of locational parameters for the screening of EIA processes. Regarding the quality analysis of EIS, the results indicate faults in the information presented in the decision-making step. The main fragilities are associated with the identification and evaluation of relevant impacts, consideration of cumulative impacts, the prediction of magnitude and the evaluation of the significance of the impacts. The previously-mentioned deficiencies of the EIS information are the main contributors to a longer processing time and to an increase in the costs which is due to the need for reanalysis of complementary documents. In addition, the environmental agency's analysts' opinion reveals a blurred perspective of EIA practice and regarding the role of the environmental agency. This obscure perspective suggests a passive and reactive positioning of actions and decisions within the environmental agency studied. Therefore, it is important to promote the valorization of the principles and foundations guiding the EIA in order to correct this perspective. Although the research findings suggest that EIA practice still has a long way to go in order to achieve effectiveness in the system studied, I identified evidence of best practice and weaknesses. This which can be used to guide actions aimed at enhancement of the EIA system as well as improvements of the development projects implemented in the State of Espírito Santo.