The incident happened just before 7 p.m. on the 1300 block of Girard Avenue.
Police say the 63-year-old owner was closing up his business when he was approached by a masked man.
The suspect reportedly hit the owner in the head with a brick and took about $3,000.
The victim was taken to Thomas Jefferson Hospital with serious head injuries but is in stable condition.
So far, no arrests have been made.