Investigators say three assailants approached the 50-year-old letter carrier on Saturday in the city's Germantown neighborhood and opened fire with paintball guns.
The Philadelphia Daily News reports the man was struck in the face, arms and back. His truck was also splattered with paint.
Police say the attackers, believed to be men between 18 and 20 years old, then fled in a car.
Newspaper reports said the men didn't demand money or try to take anything from the postal worker.