The 2008 UNASUR Constitutive Treaty (effective since 2011) confirmed its intended establishment, but does not list it with the other bodies, and does not give any details on its composition.

Article 17 states that the Parliament would be located in Cochabamba, Bolivia, and its creation would be subjected to an additional protocol.

[1] A transitory article of the Treaty states how this protocol would be created: members will appoint a "Special Commission" composed of national and regional Members of Parliament[2] who would meet in Cochabamba to draft the protocol, pending to be considered at the Fourth Summit of Unasur leaders.

During these summits the presidents would hold meetings on energy, infrastructure, education and social policies, in addition to defining a transitional formula until the full force of the treaty, which must still be approved by legislatures, comes into effect.

Powers are to be delegated to the Parliament, in order for it to consolidate the democracy in the region, to establish cooperative relationships among the member countries, to issue declarations and make recommendations, to foster the development of the representative democracy and to be in charge of the sub-organisations and institutions of Unasur.