Four fire engines and 21 firefighters and officers were called to a fire at a derelict pub with flats above in Childers Street, Lewisham.
Part of the basement was damaged by fire. Firefighters used a ladder to rescue one man from the second floor and he was taken to hospital by London Ambulance Service, suffering from smoke inhalation.
The Brigade was called at 0051 and the fire was under control at 0211. Fire crews from Deptford, New Cross, Lewisham and Peckham fire stations attended the scene.
The cause of the fire is under investigation.