Four fire engines and around 25 firefighters were called to a fire at a block of flats on Wray Crescent in Islington.
Around half of a ground floor flat in a four storey building was destroyed by the fire.
One man evacuated the building before the Brigade arrived. He was treated on scene by London Ambulance Service and was taken to hospital.
The Brigade was called at 0950 and the incident was over by 1046. Fire crews from Holloway, Kentish Town and Shoreditch fire stations were in attendance.
The cause of the fire is under investigation.