The men were transferred to Guantanamo in September 2006 after spending about three years in secret CIA prisons.
The chief prosecutor, U.S. Army Colonel Lawrence Morris, said the June 5 hearing was proof of the U.S. military's commitment to the rule of law.
"As you continue to see, the military commission's process is an orderly, fair, open legal system, remarkably similar to other trials in United States courts," Morris said. "The prosecution team will continue to work diligently to bring all cases to trial in a fair and expeditious manner, consistent with the best practices in both military and civilian courts."
All five defendants face the death penalty if found guilty of charges that include conspiracy, terrorism, attacking civilians, and murder.
At the hearing, which set the start of the trial for September, the five men refused defense lawyers, saying they would represent themselves.
Three of the men, including lead defendant Muhammad, claimed they would actually welcome the death penalty, saying it would make them martyrs.
They appeared alternately relaxed and combative, according to reporters present in the courtroom.
They chatted among themselves and frequently interrupted the tribunal's chief judge, Marine Colonel Ralph Kohlmann, during the proceedings.
Muhammad called the trial "an inquisition," and said the evidence against him had been obtained under torture.
The CIA has acknowledged interrogating Muhammad using a simulated drowning technique known as water boarding and condemned as torture by human rights observers.
Defense lawyers said they would challenge any attempt to introduce evidence tainted by abuse. But they may not get that chance if the defendants represent themselves.
U.S. Army Major Jon Jackson, a lawyer for al-Hawsawi, denounced the court for allowing the defendants to talk among themselves, saying his client was pressured by the other suspects into going without a lawyer.
"What you saw today in the courtroom, commission room, was not justice, it was ridiculous," Jackson said. "And the reason I say that is because of what happened with my client, specifically."
The trial is due to start on September 15.
compiled from agency reports