At about 5.20pm, a thief stole an orange Saracen mountain bike from outside the Londis store in The Square.
He is a white man, aged between 25-35 years old and was wearing a long-sleeved white and blue striped top and dark trousers.
Police are appealing for witnesses to the incident.
PC Chris Holland, from Bracknell police station, said: “We advise people to not leave their bicycles unlocked whilst leaving them unattended.
“We are appealing to anyone who may have information about this incident to please get in contact via the Thames Valley Police Enquiry Centre on 101.”
Witnesses should call 101 or Crimestoppers anonymously on 0800 555111.