The emergency was first declared in April by President Abdel Fattah al-Sisi for three months after the attacks on two Churches in Tanta and Alexandria killed 46 people.
The attacks were claimed by the Islamic State.
It was extended in July for a further three months.
President Sisi renewed it for a third term starting tomorrow, local media reported.
According to the decision, the armed forces and police authorities are assigned to take necessary measures to combat terror risks, maintain security across the country, and protect public and private properties, the reports said.
More From This Section
Egypt has witnessed terrorists attacks since the January 2011 revolution that toppled President Hosni Mubarak.
The attacks, targeting police, military personnel and minorities, increased after the ouster of Islamist president Mohammed Morsi in 2013 by the military following massive protests against his rule.
Hundreds of police and army personnel have been killed since then.