This thesis considers the foreign policy of Luiz Inácio Lula da Silva, the president of Brazil between 2003 and 2010. It specifically analyzes whether the foreign policy of Lula was influenced by the radical leftist ideology of his political party and whether it was characterized by a break with respect to the foreign policy of his predecessor, Fernando Henrique Cardoso. In addition, the essay will examine whether there has occurred a significant change within the group of Brazils domestic actors of foreign policy since Lula came into power. This will be a novel element in the analysis of Brazilian foreign policy that has hardly been explored before. The analysis will be conducted along the lines of four theories: foreign policy analysis, bureaucratic politics, liberal institutionalism and constructivism. Lulas three main goals of foreign policy, namely reaffirmed regional integration, a focus on South-South diplomacy and a strong emphasis on multilateralism, will be explored as cases to verify the explanatory hypotheses that were distilled from the theoretical frameworks. First, the results of the study indicate that, although Lula came from a different ideological background than Fernando Henrique Cardoso, he primarily built upon existing diplomatic traditions and behaviors, to which he adjoined new and innovative policy axes in the international relations arena. He has also changed accents with respect to a number of foreign policy themes, introduced important innovations in foreign policy and enormously widened Brazils network. Secondly, Brazilian foreign policy actors have significantly changed in Lulas 8 years in office, with some actors gaining and others losing influence. This evolution can easily be explained by the bureaucratic politics theory. Further research could be conducted in order to better understand the influence of the various domestic actors on foreign policy and to document in detail the evolution they have been undergoing during the past ten years.