Four fire engines and around 25 firefighters were called to a fire on Junction Road in Islington.
Part of a flat on the ground floor of a mid-terraced house converted into flats was damaged by the fire. Two people left the building before the Brigade arrived. One man was taken to hospital by London Ambulance Service crews and a woman was treated on scene.
The Brigade was called at 1223 and the fire was under control by 1423. Fire crews from Holloway, Kentish Town, West Hampstead and Euston fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.