Special rules apply for determining who can claim the dependency exemption for a child in cases where the parents are divorced, legally separated, or have lived apart for the last six months of the calendar year, and are not filing a joint tax return.

For these rules to apply, the support provided by the parents is combined, and the sum must be greater than one-half of the child's total support. The parent who has custody of the child for the greater part of the year is generally treated as the parent who has provided more than one-half of the child's support.

The question of who has custody of the child is normally determined under the divorce decree, separation agreement, or custody agreement. If there is no such agreement, physical custody of the child is the controlling factor.

The parent who does not have custody of the child for the greater portion of the year can take the dependency exemption if either of the following is true:

• The custodial parent waives the exemption by signing IRS Form 8332, Release of Claim to Exemption for Child of Divorced or Separated Parents, or a similar statement
• A decree or agreement signed before 1985 provides that the noncustodial parent gets the exemption, and that parent provided at least $600 for the child's support during the year.