Chicago police said at about 5:13 a.m., four suspects entered the store in the 2700 blk. of W. Touhy Ave., and approached the cash register.
One of the offenders opened fire, striking a 27-year-old man, police said.
They then took off with an unknown amount of cash from the register.
The victim was taken to St. Francis Hospital with one gunshot wound to his right leg in stable condition.
No one is in custody