1099: SSN vs ITIN

andreapgn445 — Mon, 23 Feb 2026 10:51:24 GMT

Hey everyone,
I have a contractor, who had an ITIN for most of the year, but in August he received his SSN and became an employee. For the 1099, should I use the ITIN or the SSN? I emphasize that only when he obtained his SSN, we hired him as an employee. While he was an independent contractor, he worked with his ITIN.

Re: 1099: SSN vs ITIN

Critter-3 — Sun, 15 Jan 2023 02:16:34 GMT

Use the SS# ONLY ... once an SS# is issue it must be used for everything income tax related for the entire tax year.

IRS rules to tell your employee:

Once you receive a SSN, you must use that number for tax purposes and discontinue using your ITIN. You must also notify the IRS that you have received the SSN (see below).

 It is improper to use both the ITIN and the SSN assigned to the same person to file tax returns.  It is your responsibility to notify the IRS so we can combine all of your tax records under one identification number. 

If you do not notify the IRS when you are assigned a SSN, you may not receive credit for all wages paid and taxes withheld which could reduce the amount of any refund due. 

You can visit a local IRS office or write a letter explaining that you have now been assigned a SSN and want your tax records combined. 

Include your complete name, mailing address, and ITIN along with a copy of your social security card and a copy of the CP 565, Notice of ITIN Assignment, if available.  The IRS will void the ITIN and associate all prior tax information filed under the ITIN with the SSN. 

Send your letter to: 

     Internal Revenue Service 

     Austin, TX 73301-0057 

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1099: SSN vs ITIN

Re: 1099: SSN vs ITIN