The paper briefly examines the phenomenon of internal displacement world-wide and the genesis of the United Nation’s mandate to deal with this problem. It examines key conclusions of a UN sponsored study which found that existing international law contained signifi cant gaps and grey areas in terms of meeting the needs of internally displaced persons. It also examines the origins and the content of the Guiding Principles on Internal Displacement and the normative status of these Principles. It suggests that, while not binding as such on states, the Guiding Principles have nonetheless become the most authoritative expression of minimum international standards applicable to the internally displaced and that based on state practice many, if not all, of these principles may eventually become part of customary international law. The paper also discusses the need for effective domestic implementation of the Guiding Principles, and examines how governmental authorities, the Constitutional Court and civil society organizations in Colombia, as well as inter-governmental bodies, have responded to the crisis of internal displacement in the country. While noting the adequacy of Colombia’s legislative framework on internal displacement, the paper concludes that the State has not taken the measures required to prevent future displacement or to effectively meet the protection and assistance needs of its displaced citizens.