Cairo Criminal Court confirmed Saturday death sentences against Sinai militant Adel Habara and six others for carrying out an execution-style killing of policemen in an ambush in August 2013.
Some 25 soldiers were killed in the attack.
The court had referred the seven defendants to the grand mufti last October to review their sentence, a routine procedure in capital punishment cases.
The grand mufti approved of the sentences and the court issued its final verdict in Saturday's session.
The verdict can still be appealed.
Three other defendants in the case were sentenced to life in prison while 22 others were sentenced to 15 years in prison.
Habara, who hit the headlines over his involvement in the attack, is also accused of involvement in another major militant attack in Rafah against the Egyptian army in August 2012, which left 16 soldiers killed. He is also accused of involvement in other militant operations against security forces.
A large number Islamists have been sentenced to death in similar cases over the past year.
Sinai has been beset by militant attacks by Jihadists over the past decade.
Since the ouster of former president Mohamed Morsi in July 2013, attacks by jihadists against security forces intensified.
Hundreds of militants and security forces have been killed.