Four fire engines and around 25 firefighters tackled a house fire on Gander Green Lane in North Cheam.
Part of the ground floor was damaged by fire.
A man and a woman were rescued by firefighters from the first floor. They were both suffering from smoke inhalation and taken to hospital by London Ambulance Service crews. A further man left the building before firefighters arrived. He was treated at the scene for smoke inhalation.
The fire is believed to have been accidental and involved a toaster.
A London Fire Brigade spokesperson said: “It’s really important that you always check toasters and other appliances are turned off and unplugged when not in use, unless they’re designed to be left on, like your fridge or freezer.
"Keep clutter to a minimum on your kitchen work surfaces especially near toasters and hobs as they can accidentally switch them on or catch fire."
The Brigade was called at 1024 and the fire was under control by 1139. Fire crews from Sutton, Mitcham and Wimbledon fire stations were at the scene.