Thieves cut the lock of a bike chained up outside a supermarket in town.
The pedal cycle was left locked outside Morrisons in Victoria Promenade, Northampton.
Thieves cut the lock and stole the Specialised Stumpjumper 2013 model pedal cycle which is lime green and black in colour.
It was stolen sometime between 10.30am and 11.30am on Wednesday, September 9.
Anyone with any information can call Northamptonshire Police on 101. Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.