Quick answer: A notice of objection is the formal way to dispute a CRA assessment. Corporations must file within 90 days of the notice date. Individuals get the later of that 90 days or one year after the filing due date. It can be filed online, by Form T400A or by letter.
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Key takeaways
- Corporations: 90 days from the date of the notice of assessment or determination.
- Individuals: the later of 90 days from the notice date, or one year after the filing due date.
- Filing through a CRA secure portal gets the objection assigned to an appeals officer sooner.
- A late objection can sometimes be saved by an extension request — but there is a one-year outer limit.
An objection is the formal review of an assessment by a part of the CRA that did not make it. It is a real remedy with real teeth, and it is also a deadline-driven process where the deadline is the thing most people get wrong.
Talk to the CRA first
The CRA’s own guidance is to call or write before objecting, because many disputes are resolved that way. If the issue is that you left something out of a return, that is an adjustment request, not an objection — a different and much faster process. Objecting is for cases where you believe the facts were misinterpreted or the law applied incorrectly.
The deadline
| Who | Time limit to object |
|---|---|
| Corporations | 90 days from the date of the notice of assessment or determination |
| Individuals (other than trusts) and graduated rate estates | The later of: one year after the tax filing deadline for the return, or 90 days from the date of the notice |
| Every other case, including loss determinations and RRSP or TFSA over-contribution assessments | 90 days from the date of the notice |
Note what the clock runs from: the date on the notice, not the date you opened the envelope or noticed the problem. That single fact is why reading your notice of assessment properly, and recording its date, matters.
Missing the deadline
You can apply for an extension of time, at the same time as filing the objection. To get one, you have to apply as soon as possible and no later than one year after the date the objection was due, and show that within the objection period you either could not object or intended to, that it would be fair to grant the application, and that you applied as soon as you could. If the CRA refuses the extension, you can apply to the Tax Court of Canada, which has to receive the application within 90 days of the refusal notice.
How to file
- Online through My Account, My Business Account, or Represent a Client, by selecting “Register my formal dispute.” The CRA states that filing through a secure portal gets the objection received and assigned to an appeals officer sooner, and you get a case number automatically.
- By mail or fax using Form T400A, Objection — Income Tax Act, sent to the Chief of Appeals at your Appeals Intake Centre.
- By signed letter setting out the facts and reasons, sent the same way.
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What to include
The CRA asks for your name and mailing address, a daytime phone number, the date of the notice, the tax year, your SIN or business number, the relevant facts and reasons, copies of supporting documents, and your representative’s details if you have one. The objection must be signed and dated, and for a corporation or trust an authorized officer signs it. If you are objecting to more than one assessment, file a separate objection for each.
What happens next
You receive a case number, then an appeals officer reviews the file and generally contacts you or your representative to discuss it. You have the right to request specific documents, including the auditor’s report and working papers relevant to the issues in dispute. The decision is either a reassessment adjusting your return, or a notice confirming the original assessment.
If you disagree with the decision, you can appeal to the Tax Court of Canada, which has to receive the notice of appeal within 90 days of the date the CRA sends its decision. You can also appeal if the CRA has not given you a decision within 90 days of the day you filed the objection.
What about the money
Where you file an objection, the CRA normally postpones collection action on the disputed amount until 90 days after it sends its decision — with exceptions, notably amounts you were required to withhold and remit. A large corporation has to pay 50% of the disputed amount when it files. Interest generally keeps running on an amount owing while it is in dispute, so paying reduces the interest without weakening the objection. If paying is not possible, see what happens in CRA collections.
The bottom line
Call first, note the date on the notice, and file within the limit that applies to you — 90 days for a corporation, the later of two dates for an individual. Put the facts, the reasons and the documents in the package the first time. If the underlying dispute came out of a review, our guides to CRA information requests and audit triggers are worth a read. Representation on CRA disputes is part of our tax services.
This article is general information for Canadian business owners and is current as of July 2026. It is not tax, legal or accounting advice, and it does not create a client relationship. Tax rules change and your situation is unique — please speak with a CPA before acting on anything here.
Prepared and reviewed by a Chartered Professional Accountant at EverStone CPA, an Abbotsford CPA firm working with small businesses and incorporated contractors across the Fraser Valley and Canada. About the firm → · Book a free consult →
Frequently asked questions
How long do I have to file a notice of objection?+
How do I file an objection?+
What do I need to include with my objection?+
What if I missed the deadline?+
Do I still have to pay while the objection is being reviewed?+
What happens if the CRA rejects my objection?+
Disagree with a CRA assessment?
The deadline runs from the date on your notice. Book a free consultation before it does.