Five marines still face charges in the November 19, 2005, shooting of two dozen unarmed men, women and children in Haditha, which prosecutors say came in retaliation for the death of a comrade, Lance Corporal Miguel Terrazas, who was killed by a roadside bomb.
Sharratt, 22, had been charged with three counts of premeditated murder and Stone, 35, with dereliction of duty for failing to properly report the civilian deaths.
Defence attorneys conceded that civilians were killed at Haditha but said they died during chaotic clashes with anti-government fighters after the roadside blast.
|Captain Stone and Sharrat were among eight|
marines originally charged [Reuters]
In dismissing the charges against Sharratt and Stone after what he said was an exhaustive review, Lieutenant-Genereal James Mattis cited the difficult battle conditions and a "shadowy enemy" whose forces hid among civilians.
Sharratt and Stone were among eight US marines originally charged in the Haditha case in December 2006.
Four of the defendants were charged with murder and four others with dereliction of duty.
Murder charges were dismissed in April against Sergeant Sanick Dela Cruz, who has been granted immunity from prosecution in exchange for his testimony in the case.
Dela Cruz told a military court in May that he watched his squad leader, Sergeant Frank Wuterich, shoot down five Iraqi civilians who were trying to surrender.
Later this month Wuterich, the accused ringleader in Haditha, will face a hearing to determine if he should face a court-martial.