This is the conclusion of a new study from criminologist Professor Martin Gill, who says many of us are carelessly throwing out bank and credit card statements, bills and receipts - giving both organised crime rackets and opportunistic thieves access to our identities, and our cash.
Once armed with these personal details, they can apply for bank accounts or credit cards in your name, or withdraw money from your existing accounts. And that won't just leave you out of pocket: it could also destroy your credit rating and disrupt your life.
Speaking during Britain's first National Identity Fraud Prevention Week, Professor Gill says simple actions such as shredding personal documents, redirecting mail and keeping important papers under lock and key can protect against three common dangers: mail theft, bin raiding and handbag dipping.
The first occurs where people live in flats with shared mailboxes, or when they move home without redirecting their post - allowing identity thieves to get their hands on it and start creating a bogus profile.
Figures from credit card company Capital One show that while more than 14 million items of mail go missing each year, two out of five people forget to redirect their post when moving.
The second danger involves gangs paying "bin raiders" to rifle through rubbish bags to obtain discarded bills, bank statements and receipts - so they can then apply for credit in the victim's name.
The third danger is where light-fingered thieves spirit away the bank or building society statements, payslips and passports that millions of us carry around.
Fraudsters have even been known to bribe delivery men into parting with items containing identity information.
Once they have a credit or debit card in your name, says Professor Gill, they meet little resistance in high-street shops. "Signature checks can be lax, while some male perpetrators have even managed to use cards bearing female identities."
However, there are signs that people are gradually waking up to the threat - with four out of 10 rating identity theft as a bigger concern than burglary, mugging or pickpocketing, according to a new poll by Populus. But we still aren't doing enough to protect ourselves, with three-quarters of household waste containing one or more items of value to identity thieves, reports the credit-rating agency Equifax.
If you do fall victim to the fraudsters, most of your losses should eventually be reimbursed. However, with no single organisation to turn to for help once a stolen identity comes to light, you will have to go to the considerable effort of putting things right yourself, says Jane Reay, spokeswoman for Crimestoppers.
"Identity fraud is not a victimless crime. It can take up to 300 hours of frustrating phone calls to deal with banks, credit card companies and other lenders. This is an enormous expense of time, effort and cost."
That said, there are steps you can take to avoid adding your name to the growing list of victims.
First, make sure you shred all confidential data before binning it - including bank, building society, credit card and mortgage statements and receipts.
Second, keep all personal documents secure, and even spread them in different places around your home, to make it difficult for burglars to get all the information they need.
It's also worth getting into the habit of checking receipts against your credit card and bank statements, and contacting the com-panies immediately if you come across any unfamiliar transactions.
As a blanket rule, never divulge any personal or financial details to anyone "cold calling" you - even if they claim to be from your bank, the police or another official organisation.
If you are in the least suspicious, say you will call them back, and then look up and use the correct number for that business or body.
As an internet user, meanwhile, you need to beware of scams and tricks such as "phishing", where fake websites are set up to obtain confidential customer data, and spam emails that, once clicked on, can gain access to personal information on your PC.
When buying online, look for logos of secure payment systems such as Verisign or Worldpay.
If you have been mugged or burgled, or lost crucial documents that you worry could be misused, you can add your name to the Cifas Protective Registration Service for a cost of £11.75. This alerts companies to potentially fraudulent applications.
However, the first you might know about having fallen victim is when you start receiving bills for goods or services you haven't ordered, or letters concerning debts that aren't yours.
If this happens, you should contact the bank or card issuer immediately, and then get in touch with the credit-reference agencies to see what damage has been done to your rating
You also need to contact your local police station, report the theft and request a crime number. At worst, you might even have to close all your existing bank and building society accounts and credit cards, and open new ones.
Another good way to protect yourself is by monitoring the financial information held on you by the rating agencies; postal applications start from just £2.