In a letter from its editors entitled The Times and Iraq the paper printed on Wednesday that its coverage had not been "rigorous".
"In some cases, information that was controversial then, and seems questionable now, was insufficiently qualified or allowed to stand unchallenged.
"Looking back, we wish we had been more aggressive in re-examining the claims as new evidence emerged - or failed to emerge."
The Times cited five stories - including several page one articles - written between 2001 and 2003 that had accounts of biological, chemical and nuclear weapons in Iraq.
None of the stories have ever been independently verified, some were even discredited by its own reporters or reporters at another news organisation.
But when in-house journalists wrote stories that refuted the original reporting, the corrections were buried, the Times said.
Sources for the stories depended at least in part on information from a circle of Iraqi informants, defectors and exiles bent on "regime change" in Iraq, the Times said.
"Looking back, we wish we had been more aggressive in re-examining the claims as new evidence emerged - or failed to emerge"
New York Times
Ahmad Chalabi, once a favoured Iraqi exile of the Bush administration whose headquarters in Baghdad were raided last week by Iraqi police, was cited as a named source who introduced Times reporters to several exiles.
"Complicating matters for journalists, the accounts of these exiles were often eagerly confirmed by United States officials convinced of the need to intervene in Iraq," the Times added.
"Accounts of Iraqi defectors were not always weighed against their strong desire to have Saddam Hussein ousted."
The New York Times is the US' third largest circulation newspaper behind USA Today and the Wall Street Journal.