"From tomorrow, any day could be the day of implementation," chief judge Aref Abdul-Razzaq al-Shahin said at a news conference in Baghdad.
The ruling upholds a Nov. 5 unanimous verdict in which Saddam and two of his top associates, Barzan Ibrahim al-Tikriti and Awad al-Bandar, were sentenced to "death by hanging" for the killing of 148 Shiite men and boys in the town of Dujail in 1982. Four other defendants were sentenced to prison terms ranging from 15 years to life, and an eighth was acquitted.
Saddam is currently standing trial in a separate case known as the Anfal campaign, in which chemical weapons were used to wipe out 180,000 Kurds in the 1980s.
The former Iraqi dictator is being held at Camp Cropper, an American military prison near the Baghdad airport. There is speculation he would be executed at specially built and secured gallows there instead of the Iraqi government's prison in eastern Baghdad, The New York Times reported.
Hussein's chief lawyer said that Saddam is expecting to be put to death.
"He knows the sentence has been issued from Washington, and if there's an even greater punishment than the death sentence, he'll get it," Khalil al-Dulaimi said earlier this year.
A White House spokesman said the announcement "marks an important milestone in the Iraqi people's efforts to replace the rule of a tyrant with the rule of law."
"Saddam Hussein has received due process and legal rights that he denied the Iraqi people for so long," Scott Stanzel said aboard Air Force One as President Bush was traveling to his ranch in Texas.
Talabani has said that he opposes the death penalty, but Raed Juhi, a spokesman for the High Tribunal, told the Associated Press that Saddam would be executed even if Talabani and the two vice presidents do not ratify the decision.
"We'll implement the verdict by the power of the law," Juhi said, without elaborating.