Within the last decade, South American states have become motivated to strengthen political ties and form a unified block called the Union of South American Nations (UNASUR). This political union serves as a platform for conflict resolution amongst member states as well as to find common ground for economic and infrastructural development. Furthermore, the Union is meant to bolster the region’s influence and participation in global forums and negotiations such as in the recent U.N conference on Sustainable Development (Rio+20). Although this recent conference encompassed most of UNASUR’s goals for the region (development and economic growth) it included an environmental component that the Union, up to now, seemed to have disregarded despite member states’ interest. The purpose of this research is two fold: 1) evaluate UNASUR’s actual negotiating leadership at the summit and 2) evaluate its capacity to foster cooperation between states with divergent economic and development goals while achieving environmental sustainability post Rio+20. To answer these questions, qualitative data was collected via interviews with member state representatives (official delegations and civil society) and participant observations at the summit. In addition, more extensive interviews were conducted with a similar sampling pool in the city of Quito, Ecuador where UNASUR’s secretary general headquarters is located. My preliminary interpretations of the data suggest that while integration facilitates peace talks and infrastructural development for economic growth it does not address the question of trans-boundary environmental resource management. This trend is perhaps due to trust issues, nationalist attitudes, and divergent development goals that impede a truly regional approach to sustainability. Some states claim to be more environmentally and socially conscious than others operating independently from the Union and forging their own vision of sustainability under the model of “el Buen Vivir” also known as the “XXI Century Socialism”. Is regional political integration the right approach for sustainability? My data analyses and literature review continues to find out more.