How to Object to a CRA Notice of Determination in Canada

You open your mail or your CRA account and find that your Canada child benefit or credit has been reduced, or that a claim was turned down. The document may be called a Notice of Determination. It can feel final, but it is something you are allowed to challenge.

This article explains in plain terms what a determination is, how long you have to object, what to put in your objection and what happens afterwards. Your own facts matter a great deal, so treat this as a general guide and not a substitute for advice on your file.

This article covers Canadian federal tax law, which applies in every province.

What a Notice of Determination is and what you can object to

CRA says objections can be filed against a notice of assessment, reassessment, determination or redetermination. The objection and appeal rights for assessments also apply to determinations such as the Canada child benefit, the GST/HST credit, the disability tax credit and loss determinations.

Not every piece of paper from CRA can be objected to. CRA lists examples that cannot be, including RRSP or TFSA room statements, carryforward balances, Home Buyers' Plan balances, refund interest, statements of account and nil assessments. You also cannot object to an issue on which you waived the right of objection in writing.

Objections filed late or before the notice was issued may be invalid. Wait until you actually hold the notice before you file.

The deadline to object

For an individual who is not a trust, CRA's guidance gives the later of one year after the return's filing deadline and 90 days from the date of the notice of assessment or determination. The 90 days run from the day the notice was sent, not the day you received it.

There are exceptions. Loss determinations and RRSP or TFSA over-contribution assessments have only a 90-day limit, even for individuals. If your notice is one of these, do not rely on the longer period.

Because the clock starts on the notice date, check the date printed on the notice and not the day it reached you. If you are close to a deadline, get advice quickly.

How to file and what to include

You can file online through My Account for Individuals by selecting "Register my formal dispute", and you will receive a case number. An authorized representative can file through Represent a Client. You can also mail or fax a signed letter to the Chief of Appeals, or deliver it in person. CRA says portal filing gets your objection assigned to an appeals officer sooner than paper.

CRA's paper form, T400A, was cancelled as of 2026-10-26 and replaced with Form RC592, Notice of Objection. RC592 is a fillable PDF that must be downloaded and opened in Acrobat Reader 10 or later, not in a web browser.

A notice of objection should contain the following:

• Your name, complete mailing address and daytime phone number.
• The notice date, the tax year and your SIN or other account number.
• The relevant facts and reasons, with copies of supporting documents.
• The representative's details, if you have one.
• Your signature and the date.

The objection must set out the reasons for the objection and all relevant facts. If you held back information when CRA first asked for it and give it only with your objection, the file may be sent back for a second review.

What happens after you object

Once CRA receives your objection it gives a case number, which should go in all later correspondence. The Minister must reconsider the assessment and then vacate, confirm, vary or reassess it, and notify you in writing.

Timing varies. For income tax objections resolved in August 2026, the average was 145 days for low complexity files such as credits, deductions and the Canada child benefit. These are monthly averages that change, so check CRA's current figures. The time counts only the period the file is within government control and excludes time you take to provide more information.

If CRA disagrees, it sends a Notice of Confirmation or a reassessment, and you can appeal to the Tax Court of Canada within 90 days. You can also appeal if 90 days pass after your objection was served with no decision. If the Tax Court deadline is missed, you can apply to the Court for an extension; CRA states you have one year and 90 days from the confirmation or reassessment date to apply.

If you are late, and what to do next

If no objection was made in time, you may apply to the Minister for an extension, giving the reasons for the delay and addressing it to the Chief of Appeals with a copy of the notice of objection. The application must be made within one year after the objection deadline expired. You must also show you were unable to act or had a bona fide intention to object, that granting it is just and equitable, and that you applied as soon as circumstances permitted. After one year, no extension can be granted.

• Find the date printed on the notice and work out your deadline.
• Confirm that the notice is something CRA allows you to object to.
• Gather the documents that support your position.
• Write out the facts and your reasons clearly.
• File through a secure portal if you can, and keep the case number.
• Speak with a lawyer or accountant if the deadline is close or the facts are complicated.

Frequently asked questions