Two men, one armed with a baseball bat and another with a knife threatened staff at McFadden’s service station at Breenagh, Glenswilly.
The two men, both wearing dark clothing and balaclavas, entered the shop at about 9.45pm just before staff were due to get ready to close the premises.
The men made threats to the two terrified staff members and got a small amount of cash and some cigarettes.
The two raiders then ran from the shop and escaped in a blue Rover car which was driven by a third gang member.
The men sped off in the direction of Letterkenny but the car was later found burnt out.
The shop, which has been raided before, was closed while Garda forensic officers carry out a full investigation into the terrifying robbery.