Four fire engines and around 25 firefighters were called to a small fire at a hospital on Fulham Palace Road in Fulham.
A small area on the first floor was damaged by fire. Approximately 20 people were evacuated as a precaution before being allowed to return to the building a short time later.
The Brigade was called at 0336 and the fire was under control at 0459. Fire crews from Hammersmith, Fulham, Kensington and Chiswick fire stations attended the scene.
The cause of the fire is under investigation.