Here are the profiles of the new service chiefs appointed by President Muhammadu Buhari on Tuesday 26 January.
According to the appointments, Major-General Leo Irabor replaced General Abayomi Olonisakin as Chief of Defence Staff.
Air Vice Marshal Isiaka Oladayo Amao is the new chief of air staff, succeeding Air Marshal Sadique Abubakar.
Rear Admiral Awwal Zubairu Gambo is the successor to Vice Admiral Ibok-Ete Ekwe Ibas as Chief of Naval Staff.
Major General Ibrahim Attahiru is the new chief of army staff, replacing Lieutenant General Tukur Yusuf Buratai
Major-General Leo Irabor: Chief of Defence Staff
Major-General Leo Irabor was born on October 5, 1965 and hails from Ika South LGA of Delta State.
He is a trained Engineer from Obafemi Awolowo University and holds two Masters degrees from the University of Ghana, Accra, and Bangladesh University of Professionals, Dhaka.
A one-time Theatre Commander of the Operation Lafiya Dole, he also served as commander of the Multinational Task Force in Ndjamena, Chad.
He was also Commander, Training and Doctrine Command (TRADOC).
Air-Vice Marshal I.O Amao: Chief of air staff
Air Vice-Marshal Isiaka Oladayo Amao was born on 14 Sep 1965 at Enugu. He hails from Oshogbo in Osun State.
He enlisted in the Nigerian Air Force on January 19, 1984.
Rear Admiral A.Z Gambo: Chief of Naval Staff
Rear Admiral Awwal Zubairu Gambo was born on April 22, 1966 and hails from Nasarawa LGA in Kano State.
He joined the Nigerian Navy on September 24, 1984 as a member of Regular Course 36.
He was the Director of Procurement at the Defence Space Administration.
Major-General I. Attahiru: Chief of army staff
Ibrahim Attahiru was born on August 10, 1966, and hails from Kaduna North Local Government Area of Kaduna State.
He was a former theatre commander of Operation Lafiya Dole.
He was appointed in May 2017 to replace Irabor.
Six months later, he was replaced by General Nicholas Rogers.
He was the GOC of the 82 Division, Nigerian Army before his appointment as Chief of staff of the army