Four fire engines and around 20 firefighters and officers were called to a fire at a terraced house in Drew Gardens in Greenford.
A rear bedroom on the first floor of the property was completely damaged by fire. Part of the ground floor of the property was also damaged in the blaze.
One man left the property before the arrival of the Brigade and was treated at the scene for smoke inhalation by firefighters and London Ambulance Service crews before being taken to hospital.
The Brigade was called at 0825 and the fire was under control at 0940. Fire crews from Wembley, Northolt and Park Royal fire stations attended the scene.
The cause of the fire is under investigation.