Six fire engines and around 40 firefighters were called to a house fire on Holbrook Lane in Chislehurst.
The first floor of a derelict detached house was destroyed by the blaze and the first floor was damaged. There were no reports of any injuries.
The Brigade was called at 1817 and the fire was under control by 1933. Fire crews from Sidcup and Bromley fire stations were at the scene.
The cause of the fire is under investigation.