The incident happened just after 1:30 p.m. inside Frankford Grocery & Discount on the 4700 block of Frankford Avenue.
Police say a 47-year-old man was shot once in the abdomen and once in the back.
The victim, whose identity remains unknown, was transported to Temple University Hospital.
No weapon was recovered from the scene, officials say.
There is no word on whether any arrests have been made.