The first occurred in the 1100-block of West Belmont Avenue at about 3:37 a.m.
Two male suspects entered the store and took out handguns and the store employees then ran to a back room and locked themselves in, police said.
The suspects took two cash registers and fled in an unknown direction.
The second robbery occurred at about 4 a.m. in the 2300-block of North Damen Avenue when police said a male suspect armed with a handgun entered and demanded money.
Police said the suspect took money from a register and fled in a black SUV.
No injuries were reported in either incident and no one is in custody.
Police said the robberies are not linked. Area Three detectives are investigating.