Six fire engines and around 40 firefighters dealt with a flat fire on Old Kent Road in Southwark.
A lower ground floor flat was destroyed by fire. Firefighters wearing breathing apparatus rescued a man via an internal staircase and another man left the building before the Brigade arrived. Both were taken to hospital by London Ambulance Service crews.
The Brigade's Control Officers were called at 0935 and mobilised crews from Old Kent Road, Dockhead, Dowgate, Whitechapel and Lambeth fire stations to the scene. The fire was under control by 1026.
The cause is under investigation.