Four fire engines and 21 firefighters and officers were called to a garage fire on Cranleigh Gardens in Southall during the early hours of Monday morning.
The blaze destroyed the single storey garage.
Firefighters rescued a man from the garage and he was taken to hospital by London Ambulance Service crews, where he sadly died.
The Brigade was called at 0056 and the fire was under control by 0236. Fire crews from Southall, Ealing and Northolt fire stations attended the scene. The cause of the fire is under investigation.