U.S. District Judge Leonie Brinkema previously had moved the trial to January after deciding the original Sept. 30 day failed to give Moussaoui enough time to prepare his case.
Moussaoui, a French citizen of Moroccan origin, is representing himself against charges that he conspired with the 19 suicide hijackers to commit terrorism.
The new trial date was confirmed by the U.S. attorney's office.
Brinkema has been sensitive to Moussaoui's trial preparation time because he could face the death penalty if convicted.
Moussaoui has been inundated with documents turned over by the government, according to the court-appointed legal team assisting him.
Brinkema, in a three-page order, noted that the defendant and prosecutors agreed with the postponement. She scheduled initial jury selection proceedings for May 27.
"In particular the pleadings establish that a failure to grant a continuance could result in a miscarriage of justice, and would not allow the partieis a sufficient opportunity to adequately prepare for trial," the judge said in a three-page order.
She also ordered that Moussaoui be moved to larger quarters. She called conditions in his small windowless cell "inhumane and an unreasonable barrier to his ability to work with the materials produced to him."
CBSNews.com Legal Analyst Andrew Cohen had this take on the latest trial delay.
It means two things, really. One, that Moussaoui will be better prepared to put on a defense and, two, there will be more time for prosecutors to think about whether they want to cut him a deal in exchange for the information they think he may have.
So much for the "rocket docket," right? This is a perfect example of why some cases, especially capital cases, simply cannot be rushed to trial. Even prosecutors understood that a quick Moussaoui trial this winter with so many documents involved might give him decent appeals issues down the road, especially if Moussaoui were convicted and sentenced to death.
This delay gives Moussaoui time to pour over the documents he's received from the feds and it gives the Justice Department some time to figure out whether to go forward to trial or explore a plea deal which would save Moussaoui's life but turn him into a government witness. Moussaoui's in-court rants against America suggest he's not interested in that deal but you never know.