The Supreme Prosecution of National Security released journalist Mahmoud Al-Sakka on Saturday, the Association of Freedom of Thought and Expression (AFTE) reported.
Al-Sakka, who works for the Yanair news portal, was arrested on 30 December 2015 and detained on charges of forming an illegal political movement called Youth of 25 January.
During his detention, Al-Sakka was allegedly tortured in order to force him to confess his crimes, according to Arab Network for Human Rights and Information (ANHRI). The location of his detention remained unknown for a few days following his arrest.
Al-Sakka was a member of the Tamarod movement, which played a significant role in mobilising protests against the Muslim Brotherhood regime in 2013. He also took part in the presidential campaign of Hamdeen Sabahy in 2014.
Since the ouster of Islamist former president Mohamed Morsi in mid-2013, journalists have faced threats while reporting in the field, particularly when covering protests.
Hundreds of Egyptian journalists organised a protest Wednesday in front of the Press Syndicate to demand the release of their fellow journalists.