The dissertation analyses the North American Free Trade Agreement (Nafta) and the Mercosul agreement (the South-American Agreement), especially the institutional structure and the dispute settlement mechanism of each agreement. The paper also analyses how the determining logic of each agreement affected its institutionality, creating different patterns for the relationship between State and enterprise. For this purpose, two controversies resolved under each agreement were selected for analysis, emphasizing the role played by states and enterprises involved in the conflict. It was noticed that the North-American agreement concedes broad and new benefits to the foreign investors, according to the U.S hegemonic position. Mercosul, on the other hand, implemented an essentially State-based dispute settlement mechanism, in an attempt to provide its members with an anti-hegemonic project, in which the harmony among them is crucial for the Mercosul`s success.