Six fire engines and around 40 firefighters were called to a flat fire on Loveinch Close, New Cross in the early hours of this morning.
Half of a second floor flat was damaged by fire. The blaze also damaged a small amount of the roof.
Three men left the flat before the Brigade arrived. They all subsequently went to hospital for treatment.
Around 20 residents also self evacuated the three storey block before crews arrived.
The Brigade was called at 0336 and the fire was under control at 0506. Fire crews from New Cross, Deptford, Dockhead, Old Kent Road, Peckham and Greenwich fire stations attended the scene. The cause of the fire is under investigation.