Agreements or court orders about child support payments that were made before May 1, 1997 are still valid. In these cases, the parent paying the child support can claim the payments as a deduction on his or her income tax. The parent receiving the child support must claim the payments as income on his or her income tax. This tax rule does not apply to orders or agreements made after May 1, 1997.
If your order or agreement was made before May 1997 and you want to change your tax requirements for claiming child support payments, you and the other parent must fill out a T1157 form available from the Canada Revenue Agency. Filling out this form only changes how payments are claimed for income tax purposes.