The IRS issues tax ID numbers to every individual who is subject to federal tax reporting. There are five types of federal tax identification numbers: social security number, employer ID number, individual taxpayer ID number, taxpayer ID number for pending U.S. adoptions and preparer taxpayer ID number.

Go to your local IRS Taxpayer Assistance Center and request a duplicate copy of your Federal Tax ID Number. You can locate your local TAC via the IRS website (see Resources). Alternatively, you can use your local phone directory.

Request a duplicate Social Security card by filling out an SS-5, Application for a Social Security Card. Fill out the form and take it to your local Social Security office. Bring a form of identification such as your birth certificate or your state issued driver’s license. You are limited to three cards a year. There is a lifetime maximum of 10 replacement cards.

Contact the Internal Revenue Service Business and Specialty Tax line at 800-829-4933. Advise the operator that you have misplaced your tax ID number. You need to provide your identifying information: name, address and your taxpayer ID number, if available. Request that the IRS send a duplicate copy of your federal tax ID number via mail to your residence.