The gunfire erupted around 5:10 p.m. in the 1200 block of North 42nd Street.
Authorities said the victims include three men and one woman. The victims, identified as two 45-year-old men, a 41-year-old man and a 38-year-old woman, were all hospitalized in stable condition.
Police say officers recovered six shell casings and a folding knife with a 4-inch blade at the scene.
The circumstances surrounding the shooting remain under investigation. No arrests have been announced.
Anyone with information is asked to call police at 215-686-TIPS.