Four fire engines and around 25 firefighters were called to a flat fire on Donald Woods Gardens in Tolworth.
Most of a four-roomed flat on the first floor of the building was damaged by fire. Two men were out of the building before the Brigade arrived and were taken to hospital by London Ambulance Service crews.
The Brigade was called at 0023 and the fire was under control by 0133. Fire crews from Surbiton, New Malden, Sutton and Wimbledon fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.