It's the latest of several life sentences for Mohammed Badie, who was also sentenced to death in separate trials since his 2013 arrest.
Charges have included inciting violence and planning attacks against the state.
The Cairo Criminal Court on Sunday sentenced four others to 10-15 years imprisonment on the same charges, related to the killing of seven people in 2013. The verdicts can be appealed.
In August 2013, security forces killed hundreds of people when they dispersed two pro-Brotherhood sit-ins.
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