People applying for credit cards or bank accounts could be turned down if their credit record's wrong or out of date, according to the Information Commissioner's Office.
The ICO's urging consumers to get hold of the information held about them to make sure it's accurate.
Lenders look at the credit reference file to determine your ability to repay.
Deputy Commissioner of the ICO, David Smith, says "Many of us will be relying on credit to get us through 2010.
"Out of date or wrong information in your credit file might not only stop you getting the credit you need but could have further damaging or embarrassing consequences."
Everyone has the right under the Data Protection Act to get a hold of a copy, by writing to credit reference agencies and enclosing £2.
They then have seven working days to send it to you.