If I share joint custody of my daughter but I am her custodial parent, my ex husband payes $110.00 in child support weekly which also includes back support, 38% of childcare cost and 38% of any uncovered medical expenses then I am left with the balance. He has visitation rights on Wednesday's, Fridays and every other weekend.This has been an ongoing fight between us. Who should claim her as a dependent on their taxes?

Jennifer:

In order to claim the child, you must provide MORE than half of her total support.

Based on what have said, it seems likely that YOU provide more than half of her support, so YOU would claim her.

You must "do the math" based on all of her support costs (food, clothing, housing, child care, medical care, schooling, and any other relevant support costs).

However, may I suggest that you address this issue in a more cooperative manner??

If he makes more money than you, her personal exemption is worth MORE to him than it is to you. If you both use the same tax professional, he/she can prepare the returns, then model who would get the greater tax benefit by claiming your daughter. You can then negotiate an equitable agreement as to who should claim your daughter.

If the divorce agreement does not specify who gets to claim her, such bartering/negotiation is perfectly legal. Tax professionals who served couples who are married often continue their professional relationship with both parties AFTER the divorce, and are in a perfect position to act as the "honest broker". I have done so several times over the past 15 years.

Once you come to an equitable agreement, you or he can then write a check for the difference in the refund in exchange for the written document that assigns your daughter's personal exemption to the appropriate tax return. This makes it a Win-Win situation and is one less area for argument between the divorced parents.

In most cases, because of the residency test, a child of divorced or separated parents is the qualifying child of the custodial parent. The custodial parent is the parent with whom the child lived for the greater part of the year. The other parent is the noncustodial parent.
If the parents divorced or separated during the year and the child lived with both parents before the separation, the custodial parent is the one with whom the child lived for the greater part of the rest of the year.

Noncustodial parent can claim the child if
a. The custodial parent signs a written declaration (Form 8332) that he or she will not claim the child as a dependent for the year, and the noncustodial parent attaches this written declaration to his or her return, or
b. The noncustodial parent attaches certain pages from the decree. The decree must state To be able to do this, the decree or agreement must state all three of the following.
*The noncustodial parent can claim the child as a dependent without regard to any condition, such as payment of support.
*The custodial parent will not claim the child as a dependent for the year.
*The years for which the noncustodial parent, rather than the custodial parent, can claim the child as a dependent.

This is from IRS Publication 17: Your Federal Income Tax, Chapter 3: Exemptions For Dependents
Internal Revenue Service

And AtlantaTaxExpert has given an excellent advice.

MukatA's advice is equally excellent!