He demanded a review by international specialists - but not by any from Iran or Israel.
The report from handwriting experts said a signature on a document approving rewards for intelligence agents involved in the crackdown in the 1980s was Saddam's, prosecutors said.
Saddam's lawyer Khamis al-Obaidi disputed the experts' finding and said the documents should be analysed by international experts except those from Iran because of "its obvious hostility against Arabs and Islam".
"And Israel," Saddam shouted. "Because we don't consider Israel a state, you didn't mention it. But the international community recognises Israel as a state so you must mention Israel."
After hearing the report, chief judge Raouf Abdel-Rahman adjourned the hearing until Wednesday to give the experts time to look at more documents.
In a previous session, Saddam, who appeared dressed in a black suit and white shirt, had refused to confirm nor deny his signature, and some of his seven co-defendants had said their alleged signatures on other documents were forgeries.
Saddam and the others are on trial for the deaths of 148 Shi'ites and the imprisonment and torture of others after a 1982 assassination attempt against the former Iraqi leader in the Shi'ite town of Dujail. The defendants face possible execution by hanging if convicted.
Samples refused
In their report, the handwriting experts said Saddam and his top co-defendant Barzan Ibrahim - Saddam's half brother and former head of the Mukhabarat intelligence agency - refused to give samples of their handwriting for comparison.
So the experts compared the signatures to other documents not related to the case, the report said.
The experts claimed that Ibrahim's signatures on several documents connected to the crackdown, the report said.
Among them was a memo requesting the rewards for six Mukhabarat officers involved in the crackdown, which Saddam allegedly approved. Another listed Dujail families whose farmlands were to be razed in retaliation for the incident.
Saddam and the other 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 prosecution has argued that the crackdown went far beyond the actual perpetrators of the attack and was aimed at punishing the mainly Shi'ite town.
Lawyers presented intelligence and other documents from the time showing that entire families, including women and children, were arrested in the sweep that followed and imprisoned for years without trial.
They said minors, including an 11-year-old boy, were among those sentenced to death for the attack.
Dujail residents, including several women, have testified in court that they were tortured with electrical shocks and beatings during their imprisonment.