The police were informed about robbery at a betting shop on Triq il-Qroll, St Paul's Bay, at noon on Monday.
Preliminary investigations by police who went on site found that a man with his face covered and armed with a knife entered the shop and asked for money from the employee, a 21-year-old woman.
The alleged thief escaped from the shop, taking an amount of cash with him.
No one was injured, with the police currently undergoing a search for the thief.
Duty magistrate Elaine Mercieca was informed of the case and opened an inquiry. Police investigations are ongoing.