The United Nations is very active in the field of biodiversity. It has established several conventions and has developed various instruments to protect and promote biodiversity.

Several United Nations Conventions specifically address biodiversity:
- the Convention on Biological Diversity (CBD);
- the CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora;
- the Convention on the Conservation of Migratory Species of Wild Animals (CMS or Bonn Convention);
- the Ramsar Convention on Wetlands.

In addition, UNESCO and FAO have also developed tools and instruments that help in achieving UNO's objectives and priorities on biodiversity.

The Convention on Biological Diversity (CBD) signed by Belgium in 1992, at the Rio Conference, covers all ecosystems, species and genetic resources. It links traditional conservation efforts to the economic goals by promoting sustainable and balanced management of biological resources.

The UNO has developed a Convention on the Conservation of Migratory Species of Wild Animals: the Bonn Convention or CMS. As part of this agreement ratified by Belgium in 1990, additional agreements can be concluded to protect certain species and species groups. Belgium has joined a number of these agreements such as the one on the conservation of small cetaceans in the Baltic and North Seas (ASCOBANS).

The Ramsar Convention, ratified by Belgium in 1986, specifically covers the "Wetlands" of international importance, which provide habitat to the waterfowl.

Belgium signed the CITES Convention in Washington in 1973 and ratified it in 1983. The Convention on International Trade in Endangered Species, also called Washington Convention protects more than 34,000 species of animals and plants.