Firefighters rescued a man from a burning flat in Wandsworth Bridge Road on Thursday afternoon.
Ten firefighters from two crews were called to the building, above a disused shop at number 96, at about 2pm.
Wearing breathing masks, they entered the flat and brought the man, believed to be in his 60s, to safety.
An ambulance was called but it is not believed the man required treatment and firefighters had put the fire out within half an hour.
Witnesses said smoke was visible from all floors of the three-story building. A member of staff at the nearby Boma restaurant said: "I could see smoke but no flames. The man seemed okay."
The fire brigade said a small part of the flat was damaged and have launched an investigation into the cause.
This was the second fire in Wandsworth Bridge Road in the last month after Joe's Brasserie was badly damaged by a blaze three weeks ago.