The article analyzes how indigenous and Afro-descendant communities achieved participation in the National Constitutional Assembly in 1991 in Colombia and how this process influenced the definition of new territorial institutions in which territorial autonomy and self-rule were successfully granted – against all odds. How did this happen? What circumstances facilitated the agency of these marginalized groups to such an extent that it shaped the new constitution to their benefit? The argument in this article highlights a historical juncture between a global discourse in favor of human rights, and ethnic and cultural diversity – supported by the United Nations – and a regional trend towards democratization and constitutional change. This juncture occurred during the times of a domestic peace negotiation process between the Colombian government and the country’s guerrilla groups, a process that was joined by an unusual social mobilization of underprivileged groups. Taken together, these international and national circumstances created conditions that paved the way for a successful outcome of the constitutional process, for the indigenous and Afro-descendant communities. Despite this constitutional achievement, reality has however not been easy. The territory of the two groups is rich in natural resources, something that creates opportunities for large scale agribusiness investments, and they are also well located for coca cultivation and cocaine trafficking. Such activities are not beneficial for marginalized groups. Instead, different kinds of violent fortune seekers, legal or illegal, have been attracted to the indigenous and Afro-descendant territories, which have faced threats and violence without any, or very limited, state protection.