I paid child support but the mother claimed the child on her taxes. I want to know how can I claim my child support on my taxes.

[Hal_Al]

There is a way to split the tax benefits. For future negotiations with the other parent  the following info may be of use:

 There is a special rule in the case of divorced & separated (including never married) parents. When the non-custodial parent is claiming the child as a dependent/exemption/child tax credit; the custodial parent is still allowed to claim the same child for Earned Income Credit, Head of Household filing status, and day care credit. This "splitting of the child" is not available to parents who lived together at any time during the last 6 months of the year; then only one of you can claim the child for any tax reasons. The tax benefits may not be split in any other manner.

Note in particular that the non-custodial parent can never claim the Earned Income Credit, Head of Household filing status or the day care credit, based on that child, even when the custodial parent has released the exemption to him.
The custodial parent has first priority on claiming the children on her taxes; regardless of the amount of support provided by the non-custodial parent. The non-custodial parent can only claim the child as a dependent if the custodial parent gives permission (on form 8332) or if it's spelled out in a pre 2009 divorce decree.

[rjs · Accepted solution]

Child support that you pay is not tax deductible. You cannot claim a tax deduction for it.

[xmasbaby0]

Sorry  but child support is not deductible.