Two fire engines and around 10 firefighters were called to a fire at a house converted into bedsits in South Park Crescent, Hither Green.
Part of a ground floor bedsit was damaged by fire. One man was rescued by firefighters wearing breathing apparatus and he was taken to hospital by London Ambulance Service crews.
The occupants of the property were alerted to the fire after an automatic fire alarm sounded.
The Brigade was called at 2109 and the fire was under control at 2214. Fire crews from Lee Green and Lewisham fire stations attended the scene.
The cause of the fire is under investigation.