The head of the Egyptian army appeared live on television, and announced the suspension of the constitution.
General Abdul Fattah Al-Sisi, flanked by religious and military leaders, said the chief justice of constitutional court would take the powers of the presidency.
His announcement means President Mohammed Morsi is no longer in power and Anti-Morsi protesters in Cairo’s Tahrir Square gave out a huge cheer in response to the speech.
The move follows four days of mass street protests against Mr Morsi, and an ultimatum issued by the military which expired on Wednesday afternoon.
After General Sisi’s address, both Pope Tawadros II, the head of the Coptic Church, and leading opposition figure Mohammed ElBaradei made short statements.
Mr ElBaradei said the new roadmap aimed for national reconciliation and represented a fresh start to the January 2011 revolution.
TV stations belonging to Mr Morsi’s Muslim Brotherhood went off air at the end of the speech.