Scammers could be costing Lancashire households £150m every year with the elderly at greatest risk.
The figure is revealed in documents from Lancashire County Council’s trading standards team.
The authority says the average age of a victim is 73.5 with the average scam costing its victim nearly £2,000.
In a report sent out to district councils Lancashire Trading Standards officers highlighted the issue.
A spokesman said: “We may all be vulnerable to scams at different phases of our lives and when it happens we feel embarrassed or ashamed and might want to sweep the problems under the carpet rather than talk about it.
“Anyone can be targeted but the statistics show us that it is the elderly who are at greatest risk of being taken in by a scam.”
More than 3,000 vulnerable potential victims have been identified in Lancashire.
Anyone who is worried they could be the victim of a scam should report it through Citizen’s Advice on 03454 040506 or Action Fraud on 0300 1232040