Within the United Nations, the United Nations Environment Programme (UNEP) is the lead environment body.

The United Nations Environment Programme (UNEP) was created in 1972. Its central office is in Nairobi, Kenya.

In 2012, UNEP was converted into the United Nations Environmental Assembly (UNEA). Its membership is now universal, which is a clear progress of the environmental governance reform.

However, some countries would like to go further and create a United Nations Environment Organisation (UNEO). The goal would be to establish an international code of environmental rules that render the environmental law more consistent.

The goal would also be to have harmonised relationship with other major international institutions such as the WTO (World Trade Organization) and the WHO (World Health Organization).

UNEP's missions are:
- assessing global, regional and national environmental conditions and trends;
- developing international and national environmental instruments; 
- strengthening institutions for the wise management of the environment;
- facilitating the transfer of knowledge and technology for sustainable development;
- encouraging new partnerships and mind-sets within civil society and the private sector.

UNEP works on the following topics:
- climate change,
- disasters and conflicts,
- ecosystem management,
- environmental governance,
- chemicals,
- resource efficiency.

UNEP hosts the Secretariats of several international Conventions: CITES, Basel, PIC, POPs, CMS, Montreal. The new Convention on Mercury, more commonly known as the "Minamata Convention" has recently been added to this list.  

The FPS Health actively participates in UNEP's missions and ensures the implementation of Conventions established by it.

Each year, UNEP publishes a report which reports on actions taken in the course of the year. It also publishes and widely disseminates the "Global Environmental Outlook (GEO)."

UNEP has a Liaison Office with the European Union in Brussels.