Saddam's trial judge adjourned court proceedings until April 19, to give the prosecution more time to verify signatures that are said to be those of defendants in the case trying Saddam and seven others over the execution of 148 people in the village of Dujail in 1982.
The handwriting experts said a signature on a document approving rewards for intelligence agents involved in the crackdown is that of Saddam.
The claim came at the latest session of the trial. At an earlier session Saddam refused to confirm or deny whether it was his signature.
Some of his co-defendants said their alleged signatures on other documents had been forged.
Earlier this month, the court was shown death warrants apparently signed by Saddam. If convicted, Saddam Hussein is likely to face the death penalty.
The defendants have insisted their actions in the crackdown were legal because they were taken in response to the attempt to kill Saddam as he drove through Dujail on July 8, 1982.
The Baghdad court earlier this month announced Saddam would face new charges of genocide and crimes against humanity in relation to the campaign against the Kurds in northern Iraq in the late 1980s. As many as 180,000 are believed to have died in the campaign.