Syria has until the end of today to submit all the details of its stockpile of chemical weapons.
A group of international experts are studying information already sent by the Syrian government and are expecting more today.
It's believed the country has around 1,000 tonnes of poison gas and nerve agents.
All of this is supposed to be dismantled by the middle of next year under a deal agreed last week.
To find out more about what's happening in the country, read Newsround's guide to Syria.