The report said US policymakers instead concentrated more on the agency's assessments of Iraq's weapons programme, which helped them make the case for the March 2003 US-led invasion of Iraq but which turned out to be flawed and misleading.
"Intelligence assessments on post-Saddam issues were particularly insightful," said the report.
But it added: "In an ironic twist, the policy community was receptive to technical intelligence (the weapons programme) where the analysis was wrong, but apparently paid little attention to intelligence on cultural and political issues (post-Saddam Iraq), where the analysis was right."
Administration officials justified the 2003 invasion in part on assertions that Saddam Hussein had weapons of mass destruction and was a threat to the region and the US. No such weapons have been found and investigations have blamed the CIA for huge lapses in its prewar intelligence.
The report, published in the current issue of the quarterly CIA magazine, Studies in Intelligence, was commissioned by former CIA Director George Tenet. He resigned last year after fierce criticism over the faulty Iraqi weapons assessments.
The report said the agency was largely correct in its estimate of cultural and political postwar issues and "accurately forecast the reactions of the ethnic and tribal factions in Iraq".
"In an ironic twist, the policy community was receptive to technical intelligence (the weapons programme) where the analysis was wrong, but apparently paid little attention to intelligence on cultural and political issues (post-Saddam Iraq), where the analysis was right"
The Bush administration suggested early in the Iraq war that American forces would be greeted as liberators by a grateful Iraqi people. President George Bush initially took a cavalier approach to the uprising, suggesting it would be no threat to US forces there and declaring: "Bring 'em on!"
But more than two years later the country is gripped by a deadly Sunni Muslim Arab revolt against the Shia and Kurdish-led government and US troops and nearly 2000 US troops have been killed.
Presented in July 2004, the report said prewar Iraq intelligence also concluded accurately that Saddam had no operational or collaborative ties with al-Qaida and calculated the war's impact on oil markets.
The CIA report, produced by a team led by former CIA Deputy Director Richard Kerr, was issued as the last in a series of three reports on Iraq intelligence. It is unclassified but has not been released publicly until now. The two earlier reports remain classified.
US involvement in Iraq also came under fire on Wednesday from former UN weapons inspector Scott Ritter, who said the CIA's faulty WMD intelligence only provided the pretext for a long-standing US policy of regime change.
"We had two policies in Iraq. A publicly stated policy of containment through the maintenance of economic sanctions linked to disarmament, and ... regime change. Regime change was the dominant policy," he said during an event to promote his new book, Iraq Confidential.