The first incident occurred at Goody Foot Store on California Avenue around 9:37 p.m. Dispatchers received a 911 call reporting a robbery had just occurred.
One of the suspects brandished a handgun as they fled with cash and undisclosed property from customers.
A second robbery was reported 11 minutes later from Palm Liquors & Delicatessen on Magnolia Avenue.
A storekeeper told police that the suspect, who wore gloves, took cash and magazines before fleeing. The locations are reportedly less than a half-mile apart.
No one was injured during either incident. The investigation is ongoing.
Investigators have not confirmed whether these two robberies are related.
Anyone with information on the robberies was urged to contact Sgt. Dan Russell of the Riverside Police Department at (951) 353-7106.
CNS contributed to this report.