Police say the suspects waited outside the store on Rising Sun and Adams avenues until a member of the overnight crew unlocked the front door to let a worker out of the store.
When that happened at about 3 AM, the two suspects rushed the door.
The robbers made several employees go into a storage room where they tied them up, then forced another employee to open the store's safe.
The suspects made off with about $11,000. The employees were not injured during the robbery.
Police are interviewing the workers to get descriptions of the robbers.
So far, police have only said that one robber wore a green hoodie, the other, a black hoodie. The two men remain on the loose.
There's no word yet on whether the store will open today.