Four fire engines and around 25 firefighters were called to a fire on Amhurst Road in Hackney.
Part of a flat on the ground floor of the four-storey building was damaged by the fire. Crews wearing breathing apparatus rescued a woman from the ground floor. She was treated at the scene for smoke inhalation and taken to hospital by London Ambulance Service crews. Firefighters led a further two people to safety.
The Brigade was called at 1139 and the fire was under control by 1236. Fire crews from Homerton, Shoreditch, Islington and Stoke Newington fire stations were at the scene.
The cause of the fire is under investigation.