Disputing a CRA Assessment: The Notice of Objection
The 90-day deadline, how to file, what happens to collection while the objection is open, and when the dispute moves to the Tax Court of Canada.
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
A notice of objection is the formal way to dispute a Canada Revenue Agency assessment or reassessment. Individuals have until the later of one year after the filing due date or 90 days after the notice; corporations have 90 days. An independent appeals officer reviews the file; if the objection fails, the next step is the Tax Court of Canada.
On this page
What are the deadlines?
| Taxpayer | Deadline to object |
|---|---|
| Individual or graduated rate estate | Later of one year after the return's filing due date or 90 days after the notice |
| Corporation or other trust | 90 days after the notice of assessment or reassessment |
| GST/HST | 90 days after the notice |
| Missed the deadline | Apply for an extension within one year after the deadline, showing you were unable to object or intended to, that granting it would be just and equitable, and that you applied as soon as circumstances permitted |
The clock runs from the date on the notice, not the date you received it.
How do you file?
Online through the CRA's secure portals (My Account, My Business Account, or Represent a Client) using the "File a formal dispute" service (called "Register my formal dispute" in older CRA guidance), or by mailing or faxing Form T400A to the Appeals Intake Centre. The objection must state the facts and reasons; attaching a short, organized submission with the documents that support each point gets the file assessed faster. A large corporation must describe each issue, state the relief sought for each as a dollar amount, and give the facts and reasons relied on, and any later appeal is limited to the issues and amounts specified.
What happens to collection?
For income tax, the CRA generally cannot take collection action on the disputed amount while an objection is outstanding, and for 90 days after it is decided. Interest continues to accrue, so taxpayers who expect to lose part of the dispute sometimes pay the undisputed portion. The collection pause does not apply to GST/HST or payroll source deductions, and a large corporation can be required to pay half of the assessed amount even while it objects.
What does the appeals officer do?
Reviews the auditor's file and your submission, may request more information, and decides to confirm, vary, or vacate the assessment. Many objections settle on the facts at this stage. A written decision — a notice of confirmation or a reassessment — ends the process.
What if the objection fails?
Appeal to the Tax Court of Canada within 90 days of the confirmation or reassessment. If the CRA has not decided within 90 days of the objection, you may appeal to the court without waiting.
Frequently asked questions
Can I object to a penalty or interest?
Yes, if you believe the penalty or interest was imposed or calculated incorrectly. Asking the CRA to cancel correctly charged penalties or interest because of hardship, circumstances beyond your control, or CRA error is a separate taxpayer relief request, not an objection.
Should I just file an amended return instead?
A request to adjust a return (T1 adjustment) works for errors you made; an objection is the route when you disagree with the CRA's position and want to preserve appeal rights.
Does filing an objection trigger more audit?
It does not reopen the whole return, but the appeals officer can consider related issues on the same return.
I live in the United States. Can I still object?
Yes, through the same channels; an authorized representative can also file it for you through Represent a Client.
Official sources
The CRA explains: “The time limit for corporations to file an objection is 90 days from the date of the notice of assessment or determination” — Canada Revenue Agency, Resolving your dispute: Objection rights under the Income Tax Act, https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/p148/p148-resolving-your-dispute-objection-appeal-rights-under-income-tax-act.html
The CRA explains: “This form is used to file an objection to a Notice of Assessment or a Notice of Determination issued under the Income Tax Act.” — Canada Revenue Agency, T400A Notice of Objection - Income Tax Act, https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/t400a.html
Next step
Fairlight Accounting handles U.S. domestic, cross-border (U.S.–Canada), and international tax returns, plus bookkeeping, payroll, and CFO advisory. Our Canadian Tax Desk prepares objections with the submission and documents that appeals officers act on. See pricing or book a free fit call.
Cross-border taxes, handled in one place
U.S. and Canadian filings prepared together by our U.S. and Canadian Tax Desks.
Book a free fit call