Dowd acknowledged the error in an e-mail to the Huffington Post on Sunday, the Web site reported. The Times corrected her column online to give proper credit for the material to Talking Points Memo editor Josh Marshall.
The newspaper is expected to issue a formal correction Monday. A request for comment made by The Associated Press was not immediately returned by the Times late Sunday.
The error appeared in Dowd's Sunday column, in which she criticized the Bush administration's use of interrogation methods in the run-up to the Iraq war.
In the original column, Dowd wrote: "More and more the timeline is raising the question of why, if the torture was to prevent terrorist attacks, it seemed to happen mainly during the period when the Bush crowd was looking for what was essentially political information to justify the invasion of Iraq."
Marshall last week wrote virtually the same sentence. But where Dowd's column used the phrase "the Bush crowd was," Marshall used "we were."
Dowd, who won a Pulitzer Prize for commentary in 1990, told the Huffington Post that the mistake was unintentional. She claims she never read Marshall's post last week and had heard the line from a friend who did not mention reading it in Marshall's blog.
In the updated version on the Times' site, Dowd's column had this note: "An earlier version of this column failed to attribute a paragraph about the timeline for prisoner abuse to Josh Marshall's blog at Talking Points Memo."