Balaclava wearing raiders threatened staff at a Somercotes Co-op store before stealing cigarettes and cash.
Two staff members at the Somercotes Hill store were counting stock in a back room at 10pm last night when they were set upon by two men.
The raiders forced the workers into a stock room set apart from the main store carrying large industrial-type bag, which they demanded the staff members place cigarettes and cash into.
A third man, dressed in black, also arrived st the scene while the stock was being taken and assisted in the robbery.
The three men made off in a black Skoda Fabia towards Pye Bridge.
One of the robbers had his face covered and wore a black Manchester United tracksuit zipped up. It had the football team logo on the left hand side of the garment and a Nike tick.
Police say he was of a sturdy build, between 5ft 8 inches and 6ft 4 inches in height.
The second man was dressed all in black with a hood up and his face covered.
The third man to arrive was dressed the same, but appeared to be of a slim build.
All three wore gloves.
If you have any information which could help police, call the force on 101.