Four fire engines and around 25 firefighters were called to a fire at a block of flats on Deansbrook Close, Edgware.
Most of a four roomed flat on the first floor was damaged by fire. Firefighters rescued one man from a first floor window via a short extension ladder. He was taken to hospital suffering smoke inhalation by London Ambulance Service crews. Firefighters also led one man to safety via an internal staircase.
The Brigade was called at 0136 and the fire was under control by 0250. Fire crews from Mill Hill, Stanmore and Hendon fire stations attended.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.