If I am filing separately from my husband then why do I need to fill out his information??

[MichaelL1]

When Married filing separate you will need his name and SSN --as if you itemize on your return, he has to do the same, so while separate returns, there are still some things that matter and IRS needs to know who the other party is.

[xmasbaby0 · Accepted solution]

If I am filing a separate return why do I have to list my spouse’s information on my return?

Even if you file separate returns (the worst way to file) you each have to list each other's SSN's and some other information on your own tax return.  The IRS can then cross check to make sure you are not "double dipping" for itemized deductions, dependents, etc.

If you are in a community property state, there is more information that will be needed.

Community property states:  AZ, CA, ID, LA, NV, NM, TX, WA, WI