This thesis studies the new constitutions of Bolivia and Ecuador in order to determine whether indigenous social movements have had a significant impact on policy in these two countries and looks at how these groups went about pressing for change by analyzing the strategies they have used. The research suggests that indigenous social movements in both countries have had a profound (and similar) impact on policy. This is evident in the new constitutions, which essentially embrace the concept of 'plurinacionalidad '. Furthermore, indigenous social movement groups in both countries have achieved this through the use of a wide range of interconnected strategies which evolved according to available mobilizing structures and political opportunities.