Four fire engines and 21 firefighters and officers were called to a fire at a block of maisonettes in Wilson Grove, Bermondsey.
Half of a five-roomed maisonette on the ground and first floor was damaged by fire.
Firefighters rescued a man and a woman from the first floor via a ladder. They were treated at the scene for smoke inhalation by London Ambulance Service crews.
The Brigade was called at 0742 and the fire was under control at 0840. Fire crews from Dockhead, Old Kent Road, Deptford and Whitechapel fire stations attended the scene.
The cause of the fire is accidental due to an electrical fault.