Ada County Dispatch says the report came from the 7100 block of Fairview just after 9 p.m. and that officers are currently looking for a suspect.
Maira Lopez was called in to work Wednesday night but had other obligations so the owner called someone else.
"(It's) real scary," Lopez said. "Because you never know what could happen. I have a 3-year-old that I worry about so it's just one of those crazy moments not to expect."
Lopez and other employees say they were a little nervous to come into work but will keep their guard up. The owner also announced the store will now close two hours earlier than usual to try to stop these late night crimes from happening and keep his employees safe.
Boise Police say witnesses told them a man came into the Zocoalco Supermarket and displayed a handgun, then demanded cash.
Dispatch says no injuries have been reported.
Police say the man was wearing all black clothing and a black ski mask.
Anyone with information is urged to call Crime Stoppers at 343-COPS.