Contact your bank as soon as you discover your checkbook has been stolen. This will trigger the bank's own security procedures, which usually include closing the affected account, opening a new one, and transferring funds from the old to the new account.
Speak with the banking officer assisting you about the best way to handle any checks that you recently issued that have not yet been presented for payment. If you leave funds in the old account to cover those checks, you may have to pay a substantial fee to issue a stop-payment order on the stolen checks. It may be more convenient to contact the merchants to which you issued those checks and try to replace them. Note that a stop-payment order is usually only good for six months, after which it must be renewed.
Tell your bank to contact its check verification system so that checks from your old account will not be accepted by stores. Call the leading check verification systems yourself to inform them that your checks have been stolen and that no authorizations should be issued for the affected checking account.
Report the theft to the police. In the event any of the stolen checks is forged and successfully negotiated, the bank or the merchant will try to make you pay for it anyway. You'll need that police report if you're going to dispute that charge successfully. In addition, if you note any fraudulent activity involving your financial affairs, make additional reports with the police.
Order a copy of your consumer report from ChexSystems, the reporting agency that keeps track of checking information. If you find that your checking account number is being used fraudulently, you can correct the information by following the steps found at the consumer assistance page at ChexSystems' Website (see Resources).
Safeguard yourself against identity theft by freezing your credit report, a simple step that effectively makes it impossible for new credit accounts to be opened in your name. When you want to open a new credit account, such as when applying for a mortgage or a car loan, you can easily lift the credit freeze for a short period of time, and then re-freeze it. (see Resources)