It's really important to the Americans that he's been found, because people think he knows lots of secrets about Saddam Hussein's regime.
Experts believe he may even know where Saddam is, or have information on whether there are any weapons of mass destruction.
It's not really known whether Mr Aziz was captured or gave himself up.
Wanted for war crimes
He's wanted by the US for war crimes against the people of Kuwait, Iran and his own country.
US forces still in Iraq are searching for more former members of Saddam's government.
There are 55 on their most wanted list and their faces have been put on packs of cards being given out around the country.
They've already managed to capture 12 of them.