Internal Revenue Service United States Department of the Treasury
Level Basic Advanced Military International

Amended and Prior Year Returns

Completing Amended Returns

Assembling and Submitting Form 1040X

Remember, Form 1040X can be prepared using tax software, but cannot be e-filed. Once the amended return is complete, follow these steps to assemble it for mailing and for the taxpayer's records:

  1. Print two copies of the federal amended return and, if there is a state return, print two copies of that form as well: one for the taxpayer's records and one to mail in.
  2. Have the taxpayer (and spouse if Married Filing Jointly) sign and date the bottom of the second page of Form 1040X. Review the state return instructions for where to sign and where to mail the state return.
  3. Attach all additional or corrected Form(s) W-2 or Form(s) 1099 the taxpayer received after filing the original return. (Be sure you have included any additional federal income tax withheld.)
  4. Attach any forms or schedules needed to explain the changes. Make sure the reason for amending the return is explained on Form 1040X, Part III.

Remind taxpayers who owe money and are not paying the balance due by the original due date that the IRS will send them a bill that will include any interest or penalty amounts.


Attach all affected forms and schedules when amending a return, otherwise IRS will send the amended return back to the taxpayer unprocessed.