Whenever you e-file your tax return, you're required to use a personal identification number (PIN). A PIN is any five-digit number of your choice that acts as your signature when electronically filing your tax return. If you don't have your PIN from last year, you can use your adjusted gross income (AGI) from last year's tax return to verify your identity.

Self-Select or Practitioner

You have two options when it comes to signing your electronically-filed tax return. You may choose the self-select PIN method or practitioner-PIN method. If you elect to use the self-select PIN option, you'll need to have your prior-year AGI, or last year's PIN. If you don't have your prior-year PIN, the IRS has an "Electronic Filing PIN Help" Web-based application. This will provide you with a "new" PIN to e-file your tax return.

If you use the practitioner method to file your tax return, you're not required to provide last year's PIN or AGI. However, you'll be required to sign a signature authorization form. After reviewing your return, select a five-digit number of your choice. You are prohibited from selecting all zeroes as your PIN.

Prior-Year Return

Perhaps the easiest way to get your IRS PIN from last year's taxes is to simply check that tax return. If you filed Form 1040, your AGI is located on line 37. On Form 1040A, AGI is located on line 21. AGI appears on line 4 of form 1040EZ. Your AGI from last year's tax return must match IRS records.

If you used tax preparation software like TurboTax, locate your prior-year PIN and AGI from your saved tax return. If you paid a tax preparer, visit your preparer to obtain a copy of last year's tax return.

IRS

Contacting the IRS is another way to get your prior-year PIN. Call 1-800-829-1040 to speak with an IRS customer service representative. Select the option to receive last year's AGI and PIN. Be prepared to provide your name, date of birth, address on the tax return and Social Security number. In addition, you'll be required to indicate your filing status from last year, last year's employer and the tax form you used to file. Another option at your disposal is to request a copy of last year's tax return. It may take anywhere from seven to 10 days to obtain a copy.