It crashed into the gas station in Badia del Valles, a town around 40 minutes drive north west of the Catalan capital.
Fire crews rushed to the scene of the crash before the bodies of two pilots on board were discovered.
The plane was believed to be about to land at Sabadell Airport when the crash took place.
Pictures from the scene show the tail of the aircraft sticking out of the roof of the petrol station.
The local police force, which has confirmed the fatalities, said no fire or explosion took place following the crash.
It added that the plane had departed Sabadell this morning and was returning to land.
The crash took place just yards away from the runway of the airport the plane was about to land at.