This thesis analyses the role of the anti-FTAA movement in processes of regionalisation in the Americas. The objective is to contribute to a revised new regionalisms approach by extracting some general findings from a specific case study. Three major findings are discussed in relation to the case. First, the analysis demonstrates that the anti-FTAA movement shares several of the characteristics of a regional advocacy network. It represents regional social movement cooperation, it is built on shared values, close personal bonds unites the campaign and it works as an entrepreneur in the American society. Currently we experience the beginning of a process that can lead to further integration of the movement.Second, the movement seems to develop a common, but complex identity. The We is constructed through a combination of traditional leftist and post-developmentalist discourse. The understanding of the Others may at first sight seem more one-sided since it is built on traditional leftist discourse. However, both aspects of the movement’s identity are results of compromises. The identity building in the movement can thus be said to represent an antagonism: it is ambiguous and invested with conflict. In addition, the identity can be said to be built on Latin American symbols, and not new American symbols. Still, it is regional and shared by both the North and South American protesters. Third, the anti-FTAA campaign can be said to create both intended and unintended consequences. The movement try to influence regionalisms on the continent. Through strategic framing it may change the contents of the FTAA agreement, and influences the negotiators and the civil society at large. In addition, the campaign may also have some unintended consequences. As the movement develops a regional identity, informal regionalisation evolves on the civil society level. These processes may interact and influence also formal processes of regionalisation.From this study one may abstract three main contributions to the new regionalisms debate. First, the thesis combines reflectivist and rational approaches to regionalism by basing its analysis on constructivism. This approach is seen as a bridge between the two other approaches to regionalism, and has demonstrated to be a fruitful tool for uncovering the complexity of regionalisation. Second, the thesis also demonstrates the important role social movements may play in regionalisation. The study transcends the classical state – non state divide, and argues that a variety of actors interact, influence and constitute policy-making in a region. Third, the thesis emphasises informal and unintended processes of regionalisation. Regionalisation consists of a complex web of informal and formal processes, and these are interlinked and influence each other mutually.