One W2 has an ITIN and another one has a random SSN

[sabiduria]

This is for the same client. So that tells me that he is an  authorized non-citizen resident. I put the information as it is on the W2s. The question will be, how is supposed to be done for this scenario? 

[itonewbie]

To be able to answer your question, please define "authorized non-citizen resident" and "random SSN".

[sabiduria]

well, people who are in the US and are not authorized to work use any random SSN to work. That's why they need an ITIN to fill their taxes.  

[itonewbie · Accepted solution]

These are called illegal or undocumented aliens.  Terms for tax resident status are precise and defined under §7701.  That's why the terms you used are confusing.

If your client provided a fake or stolen SSN to the employer, he/she will lose the credit for withholding because the IRS will not be able to match anything on the W-2 with your client's return to be filed with an ITIN.

Although employers should use valid SSN on W-2 and filing one with ITIN would trigger an error, income tax withholdings can at least be identified with your client's ITIN and a credit can be claimed on the return.  The same, however, cannot be said for FICA and FUTA as these withholdings will be held in a suspended account for reconciliation.