Officials from around 180 countries are meeting on Sunday to discuss how to stop the illegal trading of wildlife.
The Convention on International Trade in Endangered Species, or CITES, is being held to try and ban the buying and selling of some animal parts.
Officials at the event in Thailand will decide which animals should be protected from being killed and then sold.
Over recent years there's been a big rise in the number of animals, especially elephants and rhinos, being killed.
There is a growing demand for elephant tusks and rhino horns, especially in Asia.
In some countries polar bears and some species of sharks are allowed to be traded but only with special permits.
The Secretary-General of CITES, John Scanlon, said if the trade in ivory and horn continue at their current rate the African elephant and rhino could become extinct.
At the moment 35,000 animals and plants are listed as protected by the CITES agreement.