Six fire engines and around 40 firefighters tackled a fire at a block of flats on Kilburn Lane in Kensal Rise.
Two rooms in a three roomed flat were destroyed by the fire. One man was treated on scene and one man was taken to hospital by London Ambulance Service.
Control Officers took the first of 18 calls at 0154 and mobilised crews from Paddington, Willesden, West Hampstead and surrounding fire stations to the scene. The fire was extinguished by 0344.
The cause of the fire has been recorded as undetermined.