Four fire engines and 21 firefighters and officers were called to a flat fire on Bessborough Road in Wandsworth early this morning.
The ground floor of a two storey maisonette was severely damaged by the blaze. Fire crews wearing breathing apparatus found the body of a man on the ground floor and sadly he was later declared dead.
Firefighters evacuated around 12 people from adjacent maisonettes as a precaution.
Fire crews from Wandsworth, Fulham, Battersea and Richmond fire stations attended the scene.
The Brigade was called at 0215 and the fire was under control by 0347. The cause of the fire is under investigation.