Morsi, toppled by former army chief and now President Abdel Fattah al-Sisi in 2013, faces several trials along with top leaders of his Muslim Brotherhood.
In this case, he and 35 others are charged with being part of a vast conspiracy to destabilise Egypt involving foreign powers, the Palestinian Islamist group Hamas, Lebanon's Hezbollah and Iran's Revolutionary Guards.
Separately, another court is to deliver a verdict on April 21 in the trial of Morsi and 14 others for inciting the killing of protesters in clashes outside the presidential palace in December 2012.
Morsi, Egypt's first freely elected president, was ousted after only a year in office following protests in which millions took to the streets accusing him of monopolising power and demanding his resignation.
Since then, a government crackdown on his supporters has left more than 1,400 people dead.
Thousands more Morsi supporters have been imprisoned, and dozens sentenced to death after speedy trials the United Nations has called "unprecedented in recent history".