Mohammed Badie, top leader of Egypt's outlawed Muslim Brotherhood, was sentenced to life in jail along with 14 others Monday on charges of murder and inciting violence during clashes near Cairo last year, Reuters reported.
The session had been summoned for witness statements but the judge surprised journalists and others present by issuing a verdict, according to the report.
Badie, 71, is among hundreds of Brotherhood members already sentenced to death in mass trials that have drawn criticism from Western governments and human rights groups.
The death sentences are subject to appeal.
In what is known as the Bahr al-Azam case, Badie and the other defendants were convicted of the murder of five people and the attempted murder of 100 others during violence that broke out in Giza on July 15, 2013.
Badie and 182 Muslim Brotherhood supporters were sentenced to death in a mass trial last June over violence that erupted in Minya governorate which led to the killing of a police officer.
A court sentenced Badie to life in prison in a separate case in July for inciting violence and blocking a major road north of Cairo during protests that followed Morsi's ouster.
He received another life sentence last month, on separate counts of inciting violence in clashes near a mosque in Giza.
Badie has in the past called for a jihad (holy war) to liberate Jerusalem from Israeli rule. A video of him released by the Middle East Media Research Institute (MEMRI) shows him telling the court that his movement was not against Egypt but only against the Jews.