This thesis analyzes the development of Multinational Corporations and their changing position and effects on International Relations. The historical evolution of multinationals with important historical milestones in their development, the definition, the concepts and their changing power capabilities and effects on nation states, international organizations and international relations will be discussed in this study. This thesis will also put forward some important case studies from the biggest American multinationals giving answers to questions such as to what extend can American multinationals effect inter-state relations or do giant multinationals became equivalent actors as nation states, what kind of interdependence do multinationals create among other actors.