Four fire engines and around 25 firefighters responded to a fire on Lillie Road, Fulham.
The fire occurred in a plant room on the first floor in a hotel of 12 floors. Around 450 people were evacuated from the building as crews responded. A man, woman and child were all treated on scene for smoke inhalation by paramedics from the London Ambulance Service.
The Brigade was first called about the incident at 0759, and crews from Fuljham, Chelsea, Kensington and surrounding fire stations were sent to the scene. Firefighters were able to bring the fire under control by 1005.
The cause of the fire is under investigation.