US soldier Bradley Manning, who admitted leaking intelligence to Wikileaks, has been acquitted of "aiding the enemy".
It was the most serious of the 21 charges he was facing, and carried a sentence of life without parole in military custody.
Prosecutors had tried to prove Manning had "a general evil intent", and knew the material would be seen by al-Qaeda.
However, the judge at his court martial trial in Maryland found he was not guilty of the offence.
She found Pvt Manning guilty of most of the other charges.
He will be sentenced tomorrow.
The 25 year old former intelligence analyst still faces up to 136 years in a military prison.
Manning has been in military custody for more than 3 years.