New plans to protect elephants, rhinos and other species will be discussed at a critical meeting that begins in Bangkok on Sunday.
Around 35,000 animals and plants are at present protected by the treaty.
But with a global "extinction crisis" facing many species, this year's meeting is being described as the most critical in its history.
The CITES agreement was signed in Washington in March 1973 in an attempt to regulate the burgeoning trade in wild flora and fauna.
It entered into force in 1975 and experts say that legitimate global imports of wildlife products are now worth more than $300bn (£200bn) a year.The convention works by licensing commercial trade in species.
The process is meant to be governed by the scientific evidence of threat against an animal or a plant.
However, as CITES consists of government delegations, its decision-making is rooted in the political and economic interests of member countries.
In Bangkok, delegates from some 178 countries will face some critical decisions.
Read more of this article at the BBC website: CITES meeting on Extinction Crisis