How can I make sure no one files under my name using my social security number?

The IRS has security measures in place to verify the accuracy of tax returns and validity of social security numbers submitted. If however, you have knowledge of tax fraud being committed, you can make an anonymous report toll free to (800) 829-0433. You can contact the Social Security Administration to verify if there is another taxpayer using your social security number. The telephone number for the Social Security Administration is (800) 772-1213. For information on how to prevent identity theft contact the Federal Trade Commission (FTC) Identity Theft Hot-line (877) 438-4338.