An Egyptian appeals court has overturned death sentences issued to 149 people charged with lynching 11 police officers in August 2013, according to a report in the state-owned Al Ahram newspaper.
The court also ordered a retrial for the defendants over the attack, which occurred following the army's removal of Mohamed Morsi as president.
The attack left 13 officers dead near Cairo on August 14, 2013, the day police shot and killed hundreds of demonstrators in the capital.
However, 34 others in the same case who were not in custody could not legally be granted a retrial as they were sentenced to death in absentia.
The 183 individuals, mainly supporters of the Muslim Brotherhood group aligned with Morsi, had been found guilty of an attack on a police station on the western outskirts of Cairo in apparent retaliation for the police's deadly raids on protest camps on the same day.
IN PICTURES: Egypt Revolution - 18 days of People Power
A widely seen video from the scene - at the Kerdassa police station in Giza province - showed dead and injured police officers sitting lined up against a wall as they were abused by a crowd.
Only one of the police station's staff survived.
Two civilians caught up in the attack were also killed.
After their murder, the policemen's bodies were mutilated, with one doused in acid and another scalped.
The initial ruling in February 2015 came amid a series of death sentences in mass trials that were criticised internationally, as the government cracked down on Morsi supporters.
The grounds for the appeals court ruling were not immediately available, but the court has overturned hundreds of death sentences over the past year.