Two men armed with a handgun and a knife stole cash from a service station in a raid over the weekend.
The robbery at the Esso garage in Gringer Hill, Maidenhead, Berkshire, happened on Sunday evening.
The staff handed over an undisclosed amount of cash after being threatened by the robbers.
"Although the members of staff were not physically injured, both workers have been traumatised by the incident," said a Thames Valley Police spokesman.