Two men wielding a handgun and a knife threatened staff and escaped with cash from a KFC restaurant in Gravesend.
The robbery happened just before midnight on Sunday at the outlet in Valley Drive.
The men, both masked, walked in through the back door shortly after the restaurant had closed and threatened staff with the weapons. The cash taken had just been removed from the tills.
According to a police spokesman, both robbers have been described as white men in their 20s.
The spokesman added: "One was tall and had concealed his face by wearing a hood and a scarf wrapped around his mouth. He was carrying a small handgun.
"The other man was 5ft 10in and wore a dark blue hooded top with the hood up and a Burberry scarf over his face. He was carrying a commando-style knife with a serrated edge."
Det Insp Ian Dampier said: "No one was hurt but the whole experience was still very distressing for those staff in the shop at the time."
Anyone with information is urged to contact police on 01474 366091 or Kent Crimestoppers on 0800 555111.