Moussaoui, a French citizen of Moroccan descent, is the only person charged in the 11 September 2001 attacks on the United States.
Moussaoui was scheduled to meet US District Judge Leonie Brinkema, in Alexandria, Virginia, this week. The judge has been weighing the suspect's mental capacity, The Washington Post said on Tuesday.
The report cited sources as saying Moussaoui had notified the government of his intention to plead guilty over the objections of his lawyers.
Prosecutors and defence attorneys in the case declined to comment on the Post report.
A Justice Department spokesman was not immediately available for comment either.
Moussaoui tried to plead guilty in 2002 to four of the six charges against him, but reversed his decision a week later.
The four counts to which he first planned to plead guilty were all conspiracy charges and all carry the death penalty.
In recent letters to the government and Brinkema, Moussaoui said he was willing to accept the possibility of a death sentence, the Post reported, citing unnamed sources.
Moussaoui's attorneys declined to
comment on the Post's report
Moussaoui was arrested on immigration charges before the September 11 attacks. He has said he was not involved in the hijackings.
When he tried to plead guilty three years ago, Moussaoui said he was a member of al-Qaida and had pledged allegiance to Usama bin Ladin.
After Brinkema instructed him to think about his decision for a week, Moussaoui changed his mind.