The dependency exemption can not be split. Generally, the child is treated as the qualifying child or qualifying relative of the custodial parent. This parent is usually allowed to claim the exemption for the child if the other exemption tests are met. However, the child may be treated as the qualifying child or qualifying relative of the noncustodial parent if certain conditions are met.

The custodial parent signs a Form 8332 (PDF), Release of Claim to Exemption for Child of Divorced or Separated Parents, or a substantially similar statement, and provides it to the noncustodial parent who attaches it to his or her return. Please beware that if the custodial parent releases the exception, the custodial parent may not claim the Child Tax Credit.

Refer to Publication 501, Exemption, Standard Deduction, and Filing Information or Publication 504, Divorced or Separated Individuals, for more information on the special rule for children of divorced or separated parents.

References:

• Publication 501, Exemption, Standard Deduction
• Publication 504, Divorced or Separated Individuals
• Form 8332 (PDF), Release of Claim to Exemption for Child of Divorced or Separated Parents
• Tax Topic 354, Dependents

Source: www.irs.gov