Police said the robbery happened in the Bridgeport neighborhood's 3000-block of South Halsted Street just before 8 p.m.
Two suspects, identified only as male, entered the store and approached the clerks, police said.
One of the suspects, who was armed with a handgun, took items from the store.
No injuries were reported and no one is in custody. Area One detectives are investigating.
Police did not immediately provide further information about the robbery.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood