The King Hill Mart and Liquor store on 4702 King Hill Ave. was robbed - at gunpoint - just after 9:30 on Saturday night.
Police say the robber displayed a handgun and made away with items from the store, but no money.
It's the third time since early February this store had been robbed.
The only person in the store at the time was the female clerk.
In recent months, the St. Joseph Police Department has made a big effort to encourage stores to comply with crime-prevention laws, many of which are state laws that have been on the books for years.
They're encouraging better surveillance, better security measures, and clearing the front windows of all the advertisements that make it difficult to see inside.
"Those buildings were built with those windows for a purpose," said Sgt. Greg Gilpin from the SJPD's Support Services. "That [purpose is] to open up your property and increase visibility so that if you're outside the store you can look in and see that nothing is going on. Our officers can't stop by constantly but they can drive through the lots and look in and maybe wave at the person who's working and say 'everything's fine.'"
Sergeant Gilpin visits the scene every retail robbery in the city to give advice on how to prevent future crimes.
He says the crime prevention recommendations can seriously reduce the risk of robbery, but do not guarantee that a store won't be robbed.