Claiming a dependent, my kids dad claimed her, and he wasn't supposed to. What can o do?

[jackflower27]

He owes back child support, so he is not supposed to claim her. We both have custody

[DoninGA]

Who do the children live with for the majority of the year?

[jackflower27]

Me

[DoninGA]

See the answer below from rjs....

[rjs · Accepted solution]

All you can do at this point is file your tax return by mail. The IRS will send letters to both you and the father, to determine who is entitled to claim the child.

The IRS is not bound by your divorce decree or custody agreement, and they will not enforce the agreement. They follow the tax law. Under the tax law, whichever one of you the child lived with for more nights during the year is the custodial parent and is entitled to claim the child as a dependent. If the father is the custodial parent according to the tax law, and he refuses to release the exemption for the child to you, you will have to go to your lawyer or to the court to enforce the divorce decree or custody agreement.

[Hal_Al]

For tax purposes, there is no such thing as joint custody, regardless of what your legal agreement says. The requirement, to be custodial parent, is that the child live with you MORE than 50% of the time. One of you has to be the custodial parent and the other the non-custodial parent. The IRS goes by physical custody, not legal custody.
In the rare case (could probably only happen in a leap year like 2016), where the time that  each parent has the child is exactly equal, then the parent with the higher income (AGI) is the custodial parent, for the purpose of determining who has first priority on claiming the child as a dependent. Yes, the IRS expects you to count the numbers of nights the child sleeps at each parent's home.