Four fire engines and around 25 firefighters tackled a basement fire on Finborough Road in West Brompton.
Half of the basement and a small part of the ground floor of a mid-terraced house were damaged by the fire.
One female suffering from smoke inhalation was rescued by fire crews wearing breathing apparatus and was treated on scene by London Ambulance Service crews. One man left the property before the Brigade arrived and was taken to hospital by the London Ambulance Service. A further three women evacuated the property before the Brigade arrived.
The Brigade was called at 0954 and the fire was under control at 2338. Fire crews from Chelsea, Kensington, Battersea and Hammersmith fire stations attended the scene.
The cause of the fire is under investigation.