The White House sought to play down expectations, and has stressed that the group is only one of the avenues of advice for George Bush, the president.
Spokesman Tony Snow said: "This is not something where everybody is tensing for a punch."
The full commission, led by Baker and Hamilton, a former Democratic representative, will give a copy of the report to Bush.
On Tuesday, Robert Gates, the defence secretary-nominee, admitted that the US was not winning the war.
Gates himself was a member of the Iraq Study Group, but resigned after Bush picked him to succeed Donald Rumsfeld as defence secretary.
The Congress-mandated panel was created in March to study the situation in Iraq. It has interviewed Bush, Tony Blair, the British prime minister, foreign diplomats, officials, and academics.
The group also includes Sandra Day O'Connor, former US supreme court judge, Lawrence Eagleburger, former secretary of state; Vernon Jordan, a former ally of Bill Clinton; Edwin Meese, former US attorney-general; Leon Panetta, former White House chief of staff; William Perry, former secretary of defence; and Charles Robb and Alan Simpson, two former senators.
The panel's line-up of 10 veteran Washington insiders was expected to urge Bush to overcome his refusal to engage Iran and Syria over Iraq's plight, and recommend a gradual pullback of most US combat troops.
But the president last week cast aside speculation he would embrace recommendations on Syria and Iran and would bow to calls that he redeploy the 140,000 US troops in Iraq.
"One thing I won't do, I am not going to pull the troops off the battlefield before the mission is complete," Bush said in Latvia last week.
The non-binding report was initially seen as political cover for Bush to plot a change of strategy in Iraq, where carnage is rampant, following the deaths of more than 2,800 US soldiers and tens of thousands of Iraqis.
But Bush has also commissioned other studies on options in Iraq within his administration, and is still insisting American troops will not leave Iraq until their "mission is complete".
The Baker commission members had earlier met
Bush, Cheney and other White House officials
Bush on Tuesday got a preview of the Iraq commission's ideas for changing war policies as the White House sought to dampen the report's impact by emphasising that Bush will be listening to other voices as well.
Over lunch at the White House, Baker gave Bush a private briefing on the general outline of the conclusions, said Dana Perino, a presidential spokeswoman.
After the presentation to the president, the group is to brief Nuri al-Maliki, the Iraqi prime minister, and his team in Baghdad via secure videoconference from the White House.
Bush, to be joined by Dick Cheney, the vice president; Joshua Bolten, White House chief of staff; Stephen Hadley, national security adviser; and other senior White House aides, was to thank the commission but not comment on the specifics of its recommendations, the official said.