Tax and accounting terms
Notice of Objection Explained: How to Dispute a CRA Assessment
90 daysfrom the date of the notice is the deadline for a corporation and for a GST/HST objection. An individual can use one year after the filing deadline instead, if that is later.
Sources checked October 20263 min read
Key points
- The formal first step to dispute an assessment, reassessment or determination
- Corporations have 90 days from the date of the notice; individuals have the later of 90 days or one year after the filing deadline
- File online through a CRA account, or on Form T400A for income tax and GST159 for GST/HST
- Collection of disputed income tax is normally postponed, but interest keeps running
When to object
A notice of objection asks the CRA's Appeals Branch to review an assessment impartially. It is the right step when you believe the CRA misread the facts or applied the law wrongly. A call or letter to the office that issued the assessment can sometimes clear up a misunderstanding, and an error on your own return can often be fixed with an adjustment request, but neither stops the objection clock.
Take a personal return due in April 2025. One year after that filing deadline ran out in April 2026, so a reassessment dated in the summer of 2026 can be objected to within 90 days of its notice.
| Who or what | Deadline to object |
|---|---|
| Individual, other than a trust, or a graduated rate estate | The later of one year after the filing deadline for the return and 90 days after the date of the notice |
| Individual, for a loss determination or tax on RRSP or TFSA over contributions | 90 days after the date of the notice |
| Corporation | 90 days after the date of the notice |
| GST/HST assessment | 90 days after the date of the notice |
How to file
Online, sign in to My Account or My Business Account and register a formal dispute; a case number is issued straight away. On paper, use Form T400A for income tax or Form GST159 for GST/HST, or a signed letter, and send it to the Chief of Appeals at your Appeals Intake Centre. Set out the facts and the reasons for each issue you disagree with, and include the documents that support them.
Large corporations have extra requirements: each issue has to be described, with the relief sought, and half of the disputed amount has to be paid when the objection is filed.
If the deadline has passed
An extension can be requested, together with the objection itself, no later than one year after the original deadline. You have to show that within the objection period you could not object or have someone object for you, or that you intended to object; that you applied as soon as you could; and that granting the extension would be fair. If the CRA refuses, or gives no decision within 90 days, you can apply to the Tax Court of Canada within 90 days.
Collection, interest and appeals
Filing an objection normally postpones collection of the disputed income tax until 90 days after the CRA sends its decision. That does not apply to amounts that had to be withheld and remitted, such as payroll source deductions. Interest keeps running on any amount that turns out to be owed, so paying some or all of it during the dispute limits the interest. If you have already paid and have no decision within 120 days, you can ask for the disputed amount to be refunded while you wait.
If you disagree with the decision, you can appeal to the Tax Court of Canada within 90 days of the date the CRA sends it, or at any point after 90 days if no decision has been made.
Quick answers
How long do I have to object to a CRA reassessment?
A corporation has 90 days from the date of the notice. An individual has until the later of 90 days from the notice and one year after the filing deadline for that return.
Do I have to pay while my objection is open?
Collection of disputed income tax is normally postponed until 90 days after the decision, but interest keeps building. Amounts that had to be withheld, such as source deductions, are not postponed, and large corporations pay half the disputed amount up front.
What if the CRA does not answer my objection?
After 90 days without a decision you can appeal directly to the Tax Court of Canada.
Related pages
Official sources
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Important. This article provides general educational information, not legal or tax advice for a specific business. Rules, administrative policies, rates and deadlines can change. Confirm your facts and current obligations with the responsible government agency and a qualified adviser.