Ten fire engines and around 70 firefighters were called to a fire at a flat above a shop in Queensway in Bayswater.
A two-roomed flat on the first floor was destroyed by the fire and half of a two-roomed flat on the second floor of the four-storey terraced building was damaged. Firefighters rescued two women from the second floor of the property via a ladder. They were treated at the scene for smoke inhalation by London Ambulance Service crews and taken to hospital. Another woman and a man were also treated at the scene for smoke inhalation.
Station Manager Calum Sanders, who is at the scene, said: "The fire is under control but we will remain on scene damping down into the night.
"We would advise people to avoid the area as the road is likely to remain closed for some time."
The Brigade was called at 1809 and the fire was under control at 1957. Fire crews from Kensington, Paddington, North Kensington, Hammersmith and Soho fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.