Four fire engines and around 25 firefighters were called to a fire at a flat in Woolmead Avenue in Colindale.
Part of a first floor flat was damaged by fire. One man was rescued by firefighters and was treated at the scene for smoke inhalation.
The Brigade was called at 0425 and the fire was under control at 0553. Fire crews from Hendon and West Hampstead fire stations attended the scene.
The cause of the fire is under investigation.