Four fire engines and around 25 firefighters were called to a fire at a flat on Dalwood Street in Peckham.
Part of a first floor flat was damaged by the fire. Crews wearing breathing apparatus rescued one woman from the flat but she was sadly pronounced dead at the scene.
The Brigade was called at 0705 and the fire was under control by 0843. Fire crews from Old Kent Road, Brixton, Peckham and New Cross fire stations attended.
The cause of the fire is under investigation.