Six fire engines and around 40 firefighters were called to a fire at a flat in Watermill Way in Feltham.
A ground floor flat was destroyed by fire.
Firefighters wearing breathing apparatus rescued a man from the property but sadly he was pronounced dead at the scene. A second man left the property before the arrival of the Brigade and was taken to hospital by London Ambulance Service crews. A third man left a neighbouring property before the arrival of the Brigade and was treated for smoke inhalation before being taken to hospital.
The Brigade was called at 1916 and the fire was under control at 2021. Fire crews from Twickenham, Feltham and Heston fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and Metropolitan Police Service.