After three months of testimony, the jury deliberated for 12 days before declaring the defendants guilty on all 302 counts against them.
The trial involved defendants and witnesses from three continents and more than 50,000 pages of exhibits.
After three months of testimony, the jury deliberated for 12 days before declaring the defendants guilty on all 302 counts against them.
And prosecutors say this is just the start of a legal battle against the network allegedly headed by Saudi millionaire Osama bin Laden who tops the FBI's 10 Most Wanted list.
Six other defendants charged with conspiracy are in custody. Thirteen more suspects are still at large, including Mr bin Laden.
'Public relations'
On Tuesday two men, Mohamed Rashed Daoud Al-'Owhali, 24, and Khalfan Khamis Mohamed, 27, were found guilty of murdering 224 people, including 12 Americans in the 1998 bombings.
The other two, Wadih al-Hage, 40, and Mohamed Sadeek Odeh, 36, were convicted for their involvement in the attacks.
But terrorism investigator Steve Emerson said the trial was a "public relations campaign" and had not really gone for the alleged leaders of the bombers.
"I spoke to a senior US official who was involved in prosecuting the case hours after the verdict was in and he basically said, 'Look don't congratulate us, this is just a matter of serving justice for the families.
"'The fact is we didn't really interrupt him - Mr bin Laden - or his network, and the fact is that interrupting his network would require a much more aggressive US posture in terms of military and other types of interventionist approaches which the US is not engaged in at this point.'"
Training camps
Al-'Owhali and Mohamed, who face the death penalty, both confessed to their involvement in the attacks.
Al-'Owhali, a Saudi Arabian, drove the truck used in the Nairobi bombing. It is thought that he was supposed to die in the attack, but fled after throwing stun grenades at embassy guards.
He was arrested in Kenya and is thought to have trained in explosives at a camp in Afghanistan.
Mohamed, a Tanzanian, is also thought to have trained in camps linked to Mr bin Laden.
Prosecutors said he rented the group's bomb factory in Dar es Salaam, where he helped grind TNT for use in the bomb. He was arrested in South Africa a year after the bombings.
The other two men were found guilty of conspiracy. Odeh, a Jordanian, was an explosives specialist and technical adviser for the Nairobi bombing. He was arrested in Pakistan on the day of the bombing and sketches of the planned attack found at his home.
Al-Hage, a Lebanese-born American, was arrested five weeks after the 7 August bombings, in Arlington, Texas, where he was working in a tyre-repair shop.
US agents had been monitoring him for more than two years, in Nairobi and in Texas, suspecting him of setting up a cell in Mr bin Laden's alleged network.
They had interviewed him three times and tapped his phone lines, but were unable to stop the embassy bombings.
The FBI arrested him after a tip-off by a man who had left Mr bin Laden's organisation.