There is also nothing that will prevent him from claiming the child anyway even he is not entitled to. If he e-files first, your efile will reject because the child's SSN has already been used. If that happens you can only print and mail, claiming what you are entitled to claim. You should try to e-file first so his claim will reject.
If you both file and claim then:
The IRS will process both returns and pay any refunds. Shortly (within a year) the IRS will mail letters to both taxpayers asking if their tax return was filed in error and suggesting that they amend if they improperly claimed the child.
If neither taxpayer amends, the IRS will send a second letter asking for each taxpayers proof that they are entitled to claim the dependent, such as proof that the child physically lived with them more than half the year. School records, child care records, household receipts, medical bills, etc., that show that the child lives with you should be retained.
The IRS will evaluate each taxpayers claim and award the dependent to one taxpayer, the other will have to payback any refund received plus interest and possible penalties. The parent that had physical custody usually always wins. The lack of a signed 8332 form submitted by the non-custodial parent is a almost a certain loss for the non-custodial parent.
Do not ignore the letters or you will loose.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
