IRS Form 15103, Form 1040 Return Delinquency, is the response form the IRS sends when its records show you owed a federal income tax return and it hasn’t received one. To handle it, check the box on the form that matches your situation (you already filed, the taxpayer died, you weren’t required to file, or you have credits to apply), attach any required documents, and send it back to the address or fax number printed on your notice. Respond before the deadline on the notice, because if you don’t, the IRS can prepare a return for you using only the income it has on file — and that return will almost always cost you more than filing your own.
Why the Notice Showed Up
The IRS matches third-party records like W-2s and 1099s against filed returns. When those records show income but no Form 1040 came in for that year, the agency starts a delinquency sequence. Form 15103 typically arrives attached to one of a series of reminder notices — CP515, CP516, or the final CP518, which warns that the IRS may determine your tax for you if it doesn’t hear back.1Internal Revenue Service. Understanding Your CP518 Notice The form is how you tell the IRS which of a few situations applies to you.
One quick check before you do anything else: if you filed the return in question within the last eight weeks, it may still be processing. You can wait for it to post before responding.2Internal Revenue Service. Understanding Your CP516 Notice
The Four Response Options
Form 15103 gives you four paths. Pick the one that fits, fill in that section, and leave the others blank.3Internal Revenue Service. Form 15103 – Form 1040 Return Delinquency
You Already Filed the Return
Check the first box and enter the names on the return, the form you filed (usually Form 1040), the tax year, and the date you filed. Attach a signed, dated copy of the return. If you e-filed, print it from your tax software and sign it before you send it in. This lets the IRS locate your original filing and close the case.
The Taxpayer Died
Provide the date of death. If you filed a Form 1041 (the estate income tax return) rather than a Form 1040, check that box and enter the name on the return, the estate’s Employer Identification Number, and the tax year.
You Weren’t Required to File
Use this option if your income for that year fell below the filing threshold. The form asks for your filing status; checkboxes for age 65 or older, blind, dependent on someone else’s return, non-citizen or non-permanent resident, and work performed in another country; your total income for that year; and a brief explanation of why no return was required.
Filing thresholds change every year because they follow the standard deduction. Use the threshold for the tax year the IRS is asking about, not the current one. For reference, tax year 2026 thresholds are $16,100 for single filers under 65, $18,100 for single filers 65 or older, $32,200 for married filing jointly with both spouses under 65, and $24,150 for head of household under 65.4Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 If the notice covers an earlier year, look up that year’s numbers.
You Have a Credit or Estimated Payments to Apply
If a prior-year refund was applied to the year in question, or you made estimated payments for that year, this section tells the IRS what to do with the money. You can ask to move the credit to a different return (give the form number, tax period, and Social Security Number) or request a refund check.
Getting It Back to the IRS
Mail is the standard route. Send the completed form to the address on your notice; use the return envelope if one came with it. If you’re filing the delinquent return at the same time, staple the completed Form 1040 to Form 15103 and mail them together.
Faxing is usually faster and gives you a transmission confirmation. The fax number is on the notice. If you’re only using the form to explain that you weren’t required to file (Option 3), you can submit it through your IRS Online Account. The IRS Document Upload Tool does not accept tax returns, so a delinquent Form 1040 has to go by mail or fax.5Internal Revenue Service. IRS Document Upload Tool
Keep copies of everything you send along with proof of delivery — a fax confirmation, a certified mail receipt, or an online submission confirmation. If the IRS later says nothing arrived, that proof is what you’ll have to rely on.
What Happens If You Don’t Respond
Under 26 U.S.C. § 6020(b), the IRS can prepare a return for you, called a Substitute for Return (SFR).6Office of the Law Revision Counsel. 26 U.S. Code 6020 – Returns Prepared for or Executed by Secretary The SFR uses only the income the IRS already has on file. It does not include the Child Tax Credit, the Earned Income Tax Credit, or deductions beyond the basic standard deduction, and if you’re self-employed, the IRS is not required to allow your business expenses.7Internal Revenue Service. 4.12.1 Nonfiled Returns The tax bill that comes out of an SFR is almost always higher than what you’d owe on a return you prepared yourself.
On top of the tax, the failure-to-file penalty is 5 percent of the unpaid tax for each month the return is late, capped at 25 percent.8Office of the Law Revision Counsel. 26 USC 6651 – Failure to File Tax Return or to Pay Tax Interest runs on both tax and penalties from the original due date. If the balance sits unpaid, the IRS can file a federal tax lien or levy wages and bank accounts.
Before the tax from an SFR is formally assessed, the IRS sends a Statutory Notice of Deficiency (Notice CP3219A). You have 90 days from the date of that notice to petition the U.S. Tax Court if you disagree.9Internal Revenue Service. Understanding Your CP3219A Notice Miss the 90 days and you lose the right to challenge the assessment in Tax Court before paying.
If the IRS Already Filed a Return for You
An SFR isn’t the final word. You can still file your own return to replace it, and the route depends on whether the assessed tax has been paid.
If the SFR balance is unpaid, request audit reconsideration. Gather the documentation the IRS didn’t have — receipts, bank statements, 1099s, proof of deductions and credits — and send it in with a written explanation of each item you’re disputing. Form 12661 (Disputed Issue Verification) helps organize the disagreements. You can submit through the Document Upload Tool at irs.gov/examreply or mail everything to the IRS office that handled the assessment.10Internal Revenue Service. Audit Reconsideration Process for Correspondence Examination
If you’ve already paid the assessed tax, audit reconsideration is off the table. File an amended return on Form 1040-X claiming the credits and deductions you were entitled to, and request a refund of the overpayment.
Removing the Failure-to-File Penalty
Two paths exist for wiping out the penalty after you file the late return.
The IRS will waive it under First Time Abate if you have a clean compliance history for the three tax years before the one at issue — all required returns filed and no penalties (or any penalties removed for a reason other than First Time Abate).11Internal Revenue Service. Administrative Penalty Relief Call the number on your notice or write a letter to request it.
If you don’t qualify for First Time Abate, you can request reasonable cause relief by showing you exercised ordinary care but couldn’t file on time due to circumstances beyond your control. The IRS recognizes serious illness, natural disasters, inability to obtain records, and death of an immediate family member. Not knowing you had to file, or relying on a preparer who didn’t follow through, generally will not qualify.12Internal Revenue Service. Penalty Relief for Reasonable Cause
If You Owe and Can’t Pay Right Away
Filing a delinquent return through Form 15103 often ends with a balance due. Individual taxpayers who owe $50,000 or less in combined tax, penalties, and interest qualify for a streamlined installment agreement without submitting detailed financial statements. Apply online through your IRS account, call 800-829-1040, or visit a local Taxpayer Assistance Center.13Internal Revenue Service. Simple Payment Plans for Individuals and Businesses Interest keeps running on any unpaid balance, so putting as much down as you can up front lowers the total cost.