The World Heritage Convention laid down by the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 1972 provides the basis for the designation and management of World Heritage Sites. According to article 11.4 of the convention, UNESCO, through the World Heritage Committee, may place threatened World Heritage Sites whose conservation require major operations and for which "assistance has been requested" on a List of World Heritage in Danger. This action is intended to increase the international awareness to the threat and to encourage counteractive measures. Threats to a site can be either ascertained dangers which are proven imminent threats or potential dangers that could have adverse effects on the characteristics of a site.

In the case of natural sites, ascertained dangers include the serious decline in the population of an endangered or other valuable species or the deterioration of natural beauty or scientific value of a property by man-made activities such as logging, pollution, human settlement, mining, agriculture and major public works. Ascertained dangers for cultural properties include serious deterioration of materials, structure, ornaments or architectural coherence and the loss of historical authenticity or cultural significance. Potential dangers for both cultural and natural sites include development projects, armed conflicts, insufficient management systems or changes in the legal protective status of the property. In the case of cultural sites gradual changes due to geology, climate or environment can also be potential dangers.

Before a property is inscribed on the List of World Heritage in Danger, its condition is assessed and a potential programme for corrective measures is developed in cooperation with the state party involved. The final decision about inscription lies in the hand of the committee. Financial support from the World Heritage Fund may be allocated by the committee for listed properties. The state of conservation is reviewed on a yearly basis. Depending on the outcome of the review, the committee may request additional measures or delete the property from the list if the threats ceased to exist or may consider deletion from both the List of World Heritage in Danger and the World Heritage List. Of the two former sites, the Dresden Elbe Valley has been delisted after placement on the List of World Heritage in Danger while the Arabian Oryx Sanctuary has been directly delisted. As of 2011, there are 35 entries (17 natural, 18 cultural) on the List of World Heritage in Danger. Many of the listed sites are located in the developing world with 15 in Africa (of which five are in the Democratic Republic of the Congo), 10 in Asia, 7 in the Americas and 3 in Europe. The majority of endangered natural sites (12) is located in Africa.