The shooting happened around 12:45 a.m. Wednesday on the 3400 block of Kipp Street in North Philadelphia.
Both victims were shot multiple times. One of the brothers tried to flee in a car but stopped in the middle of the street.
They were both later rushed by medics to Temple University Hospital. One of the brothers died - the other is listed in critical condition.
Police on routine patrol witnessed the shooting and were able to apprehend three suspects. Automatic weapons were recovered nearby.
There is no word on a motive at this time.
Police have not released the identity of the victims.