The Senate panel voted 16-2 to approve Rice as Colin Powell's successor. Rice, President George Bush's current national security adviser, would be the first black woman to be secretary of state.
Despite Democrats' criticism of her role in forming US policy on Iraq, the Republican-led Senate is expected to confirm her nomination on Thursday.
The only "no" votes in the 18-member committee came from two Democrats - Senator John Kerry, who was Bush's opponent in the 2004 election, and Senator Barbara Boxer.
Kerry said Rice's testimony merely "predicts more of the same" while Boxer called it "a continuing assault on reality".
Rice is believed to have President
Rice faced tough questions during the two days of confirmation hearings.
Facing tough questions from senators on policies in Iraq, Rice admitted the Bush administration made mistakes in Iraq and was unprepared
for stabilising the country.
Democrats said the Republican Bush administration was unwilling to learn from its mistakes to change policies in Iraq, to be candid about the cost of continued deployment, or to develop a better exit strategy.
"We have made a lot of decisions in this period of time. Some of them have been good, some of them have not been good, some of them have been bad decisions, I am sure," Rice told the committee.
"We didn't have the right skills, the right capacity, to deal with a reconstruction effort of this kind," she said.
Rice's acknowledgment of mistakes followed criticism that her testimony on Tuesday belied the reality on the ground, where a raging anti-US movement has repeatedly delayed the training of Iraqi forces that would eventually take over from US troops.
Lack of flexibility
Boxer, who on Tuesday challenged Rice on the administration's case for war, urged her to change policy where necessary.
Rice has been criticised for failing
to admit foreign-policy mistakes
"It seems to me there is a rigidness here, a lack of flexibility," Boxer said.
The Bush administration, which has pursued its Iraq policy in the face of persistent criticism, has generally avoided acknowledging mistakes.
The New York Times in an editorial criticised Rice for failing to admit mistakes and worried that her unwillingness to change strategy meant she would simply try to "sell flawed American foreign policy" abroad.
Damage to credibility
Rice declined to predict for senators when US forces would return home but asserted there had been progress in training Iraqis to replace the 150,000 American troops.
Democrats, who accused the Bush administration of misleading the country into war and sending too few troops into Iraq to stabilise it, called for more candour.
"We've all got to be honest also with the world, otherwise we'll do terrible damage beyond what we've already done to our credibility," said the committee's ranking Democrat, Senator Joe Biden of Delaware.
He said the administration's inability to learn from its mistakes limited its options and ability to respond to other major foreign-policy challenges.
"It's much harder for the world to rally to our side if we have to face a truly [imminent] threat in [North] Korea or Iran," he said.