The court's decision must still be endorsed by Iraqi President Jalal Talabani, but legal officials appeared to rule out any presidential intervention by saying the death sentence cannot be commuted.
Confirming the death sentence, Appeals Court Chief Judge Arif Abd al-Razzaq al-Shahin said the execution could happen "any day."
Prominent human rights groups Human Rights Watch and Amnesty International have questioned the credibility of the trial, which they see as deeply flawed due to Iraqi government interference.
He said the sentence must be implemented within the time limit directed by the court.
Within 30 Days
"Our role is over," al-Shahin said. "Now the implementation procedure will be started, but according to our law, the sentence must be implemented within 30 days."
Iraq's Special Tribunal on November 5 sentenced Hussein to hang for crimes against humanity stemming from the killing of 148 Shi'a in the town of Al-Dujayl, following a failed assassination attempt against him in 1982.
The Appeals Court also upheld the death sentences on two of Hussein's co-defendants -- his half-brother, Barzan al-Tikriti, and former Revolutionary Court Judge Awad al-Bandar. And it recommended increasing the sentence of former Vice President Taha Yassin Ramadan, who was sentenced to life in prison. The Appeals Court said he should also be executed.
The Appeals Court decision must be ratified by Talabani and Iraq's two vice presidents.
Talabani has expressed general opposition to the death penalty. But he has previously authorized one of the vice presidents to sign execution orders on his behalf. There is an expectation that Talabani will use the same procedure in Hussein's case.
An official of the court that originally convicted Hussein said that in any case the judicial system will ensure that the former leader is executed, even if the presidency does not ratify the decision. He did not elaborate on how this could be done.
Bassam al-Husayni, a spokesman for Iraqi Prime Minister Nuri al-Maliki, was quoted by a U.S. television network as saying that hundreds of people from all walks of life and ethnic groups have volunteered to act as Hussein's hangman.
Nevertheless, the court decision is a divisive one. Many politicians -- including in the Shi'ite majority -- favor the execution, but many Sunnis -- who were the politically dominant group in the Hussein era -- see it as a revenge killing by Shi'a.
Though opinion polls show a majority of Iraqis want Hussein to be executed, some on the street do not approve of the court's sentence.
"Frankly, I do not agree with the approval of the death sentence at this time, because the situation will deteriorate further [if Hussein is executed]," said a Baghdad resident who identified himself only as Athir. "Approval of the death sentence should not be at this time. It is not in the interest of the people. We want peace and security. Actually this will further complicate the situation."
However, another resident, Muhammad Nassir, called the ruling fair, even if badly timed.
"In my opinion it is a fair ruling because this man did not do justice to the Iraqi people," Nassir said. "However, in my opinion it is not the right time for the ruling because the Iraqi people are living in a state of tit-for-tat violence and the Eid [Eid al-Adha, the Feast of the Sacrifice] is coming, so I think that it would have been better if they had postponed the ruling for a month or more."
Mixed International Reaction
International reaction in the case also differs sharply.
In the United States, White House spokesman Scott Stanzel described the confirmation of the death sentence as an "important milestone in the Iraqi people's efforts to replace the rule of a tyrant with the rule of law."
However, prominent human rights groups Human Rights Watch and Amnesty International have questioned the credibility of the trial, which they see as deeply flawed due to Iraqi government interference.
"We feel there was a huge opportunity with the trial to establish a legal and factual record of the crimes under Saddam Hussein's regime," said Tom Porteous of Human Rights Watch. "And the fact that the trial has been so deeply flawed means that the losers are really the victims of the Saddam Hussein regime."
The former Iraqi president is still involved in a separate, ongoing trial, in which he is charged with genocide and other crimes during a late 1980s crackdown that led to the deaths of an estimated 180,000 Kurds.
For a timeline of former Iraqi President Saddam Hussein's life from his rise within the ranks of the Ba'ath Party and the Revolution Command Council to his regime's ruthless persecution of perceived enemies at home and abroad, click here.