Emergency services were called to Rawson Road at the intersection of the Great Western Highway after a 35-year-old man was found injured in a car parked on the street at 12.45pm today.
9News understands that the man is Ghassan Amoun, the brother of convicted criminal Bassam Hamzy.
NSW Ambulance paramedics began treating Mr Amoun however he died on the scene.
A car was also found near Una and Smith Streets, South Wentworthville, and is believed to be related to the shooting.
At both locations, crime scenes have been identified and police have begun investigations.
Anyone with information about the shooting is urged to contact Crime Stoppers on 1800 333 000.