Three fire engines and around 15 firefighters tackled a fire at a flat on Old Kent Road in Peckham.
A small part of the second floor split level flat above a shop was damaged by the fire. One man suffering from smoke inhalation was led to safety via an internal staircase by crews wearing breathing apparatus. He was taken to hospital by London Ambulance crews.
The Brigade was called at 0335 and the fire was under control at 0437. Fire crews from Old Kent Road, New Cross and Peckham fire stations attended the scene.
The cause of the fire is under investigation.