Four fire engines and 21 firefighters and officers were called to a fire in a block of flats in Burder Close, Islington.
Part of a flat on the second floor was damaged by fire.
One woman was rescued by firefighters wearing breathing apparatus and was treated at the scene by London Ambulance Service crews before being taken to hospital.
The Brigade was called at 2135 and the fire was under control at 2221. Fire crews from Islington, Stoke Newington and Homerton fire stations attended the scene.
The cause of the fire is believed to be accidental.