The court in Amman said Ahmad Mahmoud Saleh al-Riyati was the mastermind of the 15-member terror cell linked to Al-Qaeda and Ansar al-Islam militant groups. Al-Riyati, the only suspect in custody, was sentenced to 15 years in jail, although this was quickly commuted to 7 and a half years.
Eight of the other 14, including 12 Jordanians and two Iraqis, received sentences of 15 years in jail with hard labour.
The court formally dropped charges against the remaining six, saying they had died. Military prosecution sources have said they were killed battling American forces in Iraq.
The court heard that al-Qaeda and Ansar al-Islam had recruited Al-Riyati and his cell to conduct terror attacks against US and Israeli interests in Jordan as well as to attack Western tourists and assassinate top Jordanian intelligence officers. Details of the plots were not revealed.
US forces arrested Al-Riyati in the Kurdistan region of northern Iraq and extradited him to Jordan in April 2003.