Six fire engines and around 40 firefighters were called to a fire at a derelict building in Vale Road, Stratford.
A member of public saw smoke coming from a window and dialled 999. A woman was led to safety via an internal staircase by firefighters wearing breathing apparatus. She was assessed at the scene by London Ambulance Service crews.
A small part of the basement was damaged by fire.
The Brigade was called at 2128 and the fire was under control at 2350. Fire crews from Stratford, Plaistow, Leytonstone, and Leyton fire stations attended the scene.
The cause of the fire is under investigation.