Masked men targeted a security guard delivering cash to a bank in Bamber Bridge.
The three men, who were wearing balaclavas, jumped out of a blue BMW at around 6am on Wednesday July 19 and chased the security guard near to the RBS on Station Road, say police.
A police spokesman said: "Early this morning, while a guard was filling the ATM at RBS a blue BMW pulled up.
"Three men wearing balaclavas jumped out and chased the guard who dropped a cassette containing a substantial amount of cash.
"The men picked up the cassette and made off."
An RBS spokesman said:“We can confirm that an incident took place this morning, nobody was injured during the incident and we are fully cooperating with the police in their investigation”.
A cordon was placed around the area and a heavy police presence was noted in the area.
Police are investigating and enquiries are on-going to trace the offenders.