President Bush was informed just before dawn today that US troops had captured the ousted Iraqi dictator near his home town of Tikrit.
Saddam had been the focus of a massive manhunt since the US military tried - unsuccessful - to kill him in the opening hours of the war. Aides said President Bush will speak to the press at 5 p.m. today after meetings with his top advisers.
"The message to the Iraqi people is that the blanket of fear is beginning to lift," a senior White House official said.
The news could boost President Bush's standing in the polls. But the official added: "There are unfortunately still people in Iraq who have no future because their loyalties are to Saddam. We expect they will continue to fight to the death."
More than 300 US soldiers have been killed in action since US-led forces invaded Iraq in March to oust Saddam - nearly 200 of them in guerrilla attacks since President Bush declared major combat over on May 1st.
Aides said Defence Secretary Mr Donald Rumsfeld was the first to deliver the news to the president yesterday afternoon while he was at the presidential retreat of Camp David. Vice President Dick Cheney and members of the president's Cabinet were told soon thereafter.
President Bush, who returned to the White House last night, received final confirmation of Saddam's capture from national security adviser Ms Condoleezza Rice shortly after 5 a.m. (10 a.m. Irish time) today.