The main goal of this dissertation is the analysis of the impact of the portuguese democratic transition on the nature of the country s foreing policy. More specifically, our purpose is to analyse how the change caused by the political transition in the state-society relations determined Portugal s accession to the European Economic Community (EEC) in 1986. More than an economic necessity, EEC membership meant a new identity for Portugal, from an overseas empire to an modern, european country. In the first chapter, after a theoretical debate, where we highlight the interaction between the domestic and the international arenas, we narrow our focus and try to explain the relational ties between political change and foreign policy. In that sense, it is important to identify the impact of the mode of transition on the nature of the new regime and, as a consequence, on its foreign policy. There, we classify the portuguese transition as a reform throug rupture. Then, using a theoretical model, we try to understand the relevance of the state-society relation as a variable for explaining foreign policy change. In the second and third chapters, we analyse the relational ties between this variable and the portuguese foreign policy under the Estado Novo and after the Carnation s Revolution.