The 90-year-old Mubarak, whose nearly three-decade rule was ended by a popular uprising in 2011, could be seen walking into the courtroom with a cane.
Morsi was removed from power by the military in 2013 amid mass protests against his divisive rule. The jailed former leader now faces an array of charges in multiple court cases.
Wednesday’s trial concerns a jailbreak staged by Morsi and other leaders of the Muslim Brotherhood group during the 2011 uprising.
Mubarak however refused to answer most questions, saying he needs permission from President Abdel-Fattah el-Sisi and the military.