A three-year-old girl raised the alarm when she discovered a fire in her home last night.
The child told her mother that part of a bedroom was alight and firefighters were called to the property in Edith Road, Selhurst, at about 9.30pm.
Crews from Croydon and Norbury fire stations took about an hour to get the blaze under control.
It caused significant damage to the top floor of the three storey building but the firefighters managed to stop it spreading to the floor below, the ground floor flat, and neighbouring properties.
Both the child and her mother were taken to hospital by ambulance as a precaution as they were suffering from mild smoke inhalation.
The cause of the fire is still under investigation The property did not have a working smoke alarm so firefighters gave fire safety advice to people living in neighbouring properties.
They will be back later in the week to tell other people in the street about the importance of having a working smoke alarm.