Four fire engines and around 25 firefighters were called to a fire at a detached house converted into flats on Melrose Road in Wandsworth.
Part of a flat on the lower ground floor of the four-storey building was damaged by the fire. Crews wearing breathing apparatus rescued one man. He was treated on scene by London Ambulance Service crews and taken to hospital.
The Brigade was called at 0821 and the fire was under control by 0915. Fire crews from Wandsworth, Battersea and Tooting fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.