Gunfire rang out along the 7200 block of Walker Street just after 3 a.m., leaving one man dead and another in the hospital.
Police said both victims lived at the home, which served as a rooming house.
Authorities say two men had knocked on the back door and were let inside.
According to investigators, the men went downstairs and shot a 49-year-old man multiple times. He was conscious, stable and taken into surgery.
As the men were leaving, police say they shot the second victim, who was sitting in the driver's seat of a BMW in the back alley.
Police say the man, believed to be in his mid-30s, had just returned home. He was pronounced dead on the scene.
"We don't have a motive for the shooting, but clearly this is a home invasion shooting because the initial victim -- the 49-year-old male -- was shot after two males knocked on the door, were let in the property, and then they went, found him in the basement, and shot him. And the second male was shot when these two perpetrators exited the rear of the property," explained Philadelphia Police Chief Inspector Scott Small.
Police are checking area surveillance in the area in hopes of getting a description of the suspects.