Can You Have Both an ITIN and SSN? Notifying the IRS and Back Credits

No, you cannot actively hold both an ITIN and an SSN. Federal tax regulations treat the Individual Taxpayer Identification Number as a stand-in that exists only for people ineligible for a Social Security Number, so once the Social Security Administration issues you an SSN, your ITIN has to be retired. You need to notify the IRS in writing (or in person), get your prior tax records combined under the new number, and then update your employer, your bank, and the Social Security Administration so nothing you earned or paid gets stranded under the old number.

Why the Rule Is One Number Per Person

Under 26 CFR § 301.6109-1, anyone who already holds an ITIN and later receives an SSN must use the SSN for all future tax filings and tell the IRS about the change. The same regulation bars the IRS from issuing an ITIN to a person who already has or is entitled to an SSN.¹ There is no window where both numbers stay active.

The reason is mechanical. The tax system links every person to one identifying number. Two active numbers produce duplicate records, and income reported under one may not line up with withholdings reported under the other. That mismatch delays refunds, triggers IRS notices, and leaves gaps in the earnings history the Social Security Administration keeps for you.

How to Notify the IRS

You have two options: visit a local IRS office in person, or send a letter by mail.² Either way, the IRS needs the same items:

Your full legal name, exactly as it appears on the new Social Security card
Your current mailing address
Your ITIN (the nine-digit number from prior returns)
A copy of your Social Security card
A copy of the CP 565 notice that originally assigned your ITIN, if you still have it

If you mail the request, state plainly that you have been assigned an SSN and want your tax records combined. Send everything to:

Internal Revenue Service
Austin, TX 73301-0057

That is the address the IRS designates for ITIN-to-SSN notifications.² A different Austin P.O. Box appears elsewhere on the IRS site for new ITIN applications and name changes; don’t use it for this purpose.³

The IRS does not publish a specific timeframe for processing rescission requests. For context, new ITIN applications take about seven weeks outside of filing season and nine to eleven weeks between January 15 and April 30.⁴

What Happens Once Your Records Are Combined

After the IRS processes the notification, it voids the ITIN and links prior filings, withholdings, and payments made under that number to your SSN.⁴ You get proper credit for what you already paid, and every future return, W-4, and financial document uses the SSN.

Skip the notification and the IRS may not connect employer-reported wages and withholdings to your SSN account, which can shrink refunds and create discrepancies between your return and what employers reported.⁵

Going Back for Tax Credits You Couldn’t Claim Before

Several valuable credits require a valid SSN, so ITIN filers were shut out of them.⁶ Getting an SSN sometimes opens the door to amending prior returns, but the rules differ by credit.

Earned Income Tax Credit

To claim the EITC, you (and your spouse, if filing jointly) must have had a valid SSN issued on or before the due date of the return for that tax year, including extensions.⁷ If you didn’t have the SSN by that deadline, receiving it later doesn’t let you go back and claim EITC for those years.⁸ You can claim it going forward, starting with the first year your SSN was in hand by the filing deadline.

Child Tax Credit

The Child Tax Credit works differently. The SSN requirement applies to the qualifying child, not the parent. If your child already had an SSN valid for employment during years you filed under an ITIN, you may be able to amend those returns now and claim the credit retroactively.⁹

The Three-Year Window

Amended returns claiming a refund generally must be filed on Form 1040-X within three years of the original filing date (including extensions), or within two years of paying the tax, whichever is later.¹⁰ The window moves. Waiting a few months after you get your SSN can cost an entire year of eligibility, so amend as soon as your records are combined.

Fixing Your Social Security Earnings Record

The IRS notification handles your tax file. It does not fix your earnings history at the Social Security Administration, which runs on a separate database. If wages were ever reported to the SSA under your ITIN, those earnings may be missing from your Social Security statement, which reduces the retirement or disability benefit you eventually receive.

The SSA lists wages reported under “the wrong name or Social Security number” and wages earned “using an SSN that didn’t belong to you” as common causes of missing earnings.¹¹ Both fit the ITIN situation.

Gather anything that proves the missing wages: W-2s, tax returns, pay stubs. If you no longer have documents, write down what you remember—employer names, locations, dates, amounts, and the ITIN you used at the time. Then call 1-800-772-1213, visit a local office, or mail a request to your local Social Security office.¹¹ Form SSA-7008 (Request for Correction of Earnings Record) is built for this; enter your former ITIN in the field for other Social Security numbers used by you or your employer to report wages.¹²

Updating Your Employer

If your employer uses E-Verify, you’re required to update the Social Security number field on your Form I-9 once you receive your SSN, then initial and date the change.¹³ The I-9 instructions also state directly that an ITIN should never be entered as an SSN on that form. Submit a new Form W-4 too, so your employer reports wages under the correct number from that point on. If W-2s keep going out under your old ITIN, the wages may fail to credit properly on either side—tax or Social Security.

Updating Banks and Other Accounts

Any bank, brokerage, or other institution where you opened an account with your ITIN needs your new SSN. These institutions report interest, dividends, and other income to the IRS using the taxpayer identification number on file. Once your ITIN is voided, income reported under it may not match your SSN-based return, which triggers notices or refund delays.

Spouses and Dependents Who Get an SSN

The same process applies to a spouse or dependent on your return who transitions from an ITIN to an SSN. Notify the IRS for each person so their ITIN can be voided and their records merged.⁴ For dependents this can matter immediately, because a child’s SSN may unlock the Child Tax Credit for the current year and for amended returns still inside the three-year window.

One letter can cover several people as long as each person’s details are clearly separated. Include full name, ITIN, a copy of the new Social Security card, and the CP 565 notice if available. Send it to the Austin, TX 73301-0057 address or bring it to a local IRS office.²

1
eCFR. 26 CFR 301.6109-1 – Identifying Numbers
2
Internal Revenue Service. Additional ITIN Information
3
Internal Revenue Service. How to Apply for an ITIN
4
Internal Revenue Service. Individual Taxpayer Identification Number (ITIN)
5
Internal Revenue Service. Understanding Your CP565 Notice
6
Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) Reminders for Tax Professionals
7
Office of the Law Revision Counsel. 26 USC 32 – Earned Income
8
Internal Revenue Service. Topic No. 601, Earned Income Credit
9
Office of the Law Revision Counsel. 26 USC 24 – Child Tax Credit
10
Office of the Law Revision Counsel. 26 USC 6511 – Limitations on Credit or Refund
11
Social Security Administration. How to Correct Your Social Security Earnings Record
12
Social Security Administration. Request for Correction of Earnings Record
13
USCIS. Instructions for Form I-9, Employment Eligibility Verification