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Notice of objection
Not the day it arrived, and not the day you opened it. If a notice of assessment or reassessment says something you disagree with, there is a formal process for challenging it and a hard deadline attached. Missing it is recoverable, but it costs you options.
An objection is a formal legal dispute. Plenty of people file one when something simpler and faster would have fixed the problem, and a few do the reverse and let a real deadline expire. There are four different doors and they are not interchangeable.
| Your situation | What you need |
|---|---|
| You made a mistake on your own return Forgot a slip, missed a deduction, wrong number |
An adjustment request, not an objection. T1-ADJ for individuals, an amended return for a corporation. Faster, simpler, no deadline pressure |
| The CRA changed something and you disagree Denied an expense, added income, reassessed you |
A notice of objection. This page. Watch the 90 days |
| You accept the tax but the penalties and interest are the problem Illness, disaster, CRA delay, financial hardship |
Taxpayer relief, form RC4288. A separate discretionary process, and it does not extend your objection deadline |
| You never reported it in the first place Unfiled returns, unreported income |
The Voluntary Disclosures Program, which is a different thing entirely and works best before the CRA finds you |
Before any of that, try the phone. A fair number of reassessments come from a document the CRA did not receive or could not match. Calling and sending the missing paper resolves it without a formal process. The CRA's own guidance says to contact them first. Just do not let an informal conversation run past day 90, because the deadline does not pause while you talk.
The later of these two:
The second one catches people by surprise, usually pleasantly. If you were reassessed shortly after filing, the one year test may give you considerably more than 90 days. It is worth checking rather than assuming.
90 days from the date of the notice. There is no one year alternative. Corporations get the short deadline and no cushion, which is why a notice landing on a business owner's desk in a busy month is the classic way this gets missed.
You can apply for an extension of time, and you have one year after the objection deadline expired in which to ask. You have to explain why you were late. The CRA can refuse, and if it does there is a further route through the Tax Court. This is a rescue, not a plan.
The date that matters is printed on the notice. Not the postmark, not the day it turned up, not the day you got round to reading it. If you have a notice in front of you, find the date on it and count. If the number is under thirty, ring somebody today.
An objection is not a complaint. It is a document that has to state a position and support it. At minimum:
You can file online through My Account, My Business Account or Represent a Client, or on paper using Form T400A, or by writing to the Chief of Appeals at the appropriate Appeals Intake Centre. The form is not compulsory. A properly constructed letter does the job.
A corporation is a large corporation for this purpose if taxable capital employed in Canada, across it and its related corporations, exceeds $10 million at the end of the year. If that is you, the objection must describe each issue, quantify the relief sought for each issue, and set out the facts and reasons relied on for each. Issues not properly raised at this stage can be shut out later, so the drafting genuinely matters.
For income tax, generally no. You are not required to pay the disputed amount while an objection or appeal is outstanding. Two things to understand about that:
Amounts the CRA treats as held in trust, such as payroll source deductions and GST/HST, are handled differently from ordinary income tax, and collection can continue. If your dispute involves those, ask about it specifically rather than assuming the pause applies.
An appeals officer, independent of the auditor who made the assessment, reviews the file. They will usually make contact to discuss it and will often ask for more. The outcome is a notice of confirmation, or a reassessment that changes the number, in whole or in part.
If it is confirmed and you still disagree, the next step is an appeal to the Tax Court of Canada, generally within 90 days of the decision. The informal procedure at the Tax Court is designed to be usable without counsel for smaller amounts, though there are limits on what it can award. Once you are at that stage you are in litigation, and a tax lawyer is the right call.
One note on privilege. Communications with your accountant are not protected by solicitor-client privilege. For an ordinary disagreement about a denied expense that does not matter. If the assessment involves alleged gross negligence penalties or anything with criminal exposure, involve a tax lawyer early, and they can bring an accountant in under privilege.
Usually it starts with reading the notice and the audit correspondence, which tells you fairly quickly whether the CRA has made an error, applied a defensible position you may not like, or simply never received something. Those three lead to different answers, and one of them costs you nothing.
If an objection is the right route, the work is assembling the position, the facts and the documents into something an appeals officer can act on, filing within the deadline, and handling the correspondence through to the decision. Fixed fee, agreed in writing first.
For individuals, the later of 90 days from the date on the notice or one year after the filing due date of that return. For corporations, trusts and GST/HST, 90 days from the date on the notice. The clock runs from the date printed on the notice, not from when you received it.
You can apply for an extension of time, within one year after the objection deadline expired, explaining why you were late. The CRA may grant or refuse it, and a refusal can be taken further. It is worth trying, and much better not to need it.
No. The form is available and it is convenient, but an objection can be filed online through My Account, My Business Account or Represent a Client, or as a letter to the Chief of Appeals. What matters is content, not format.
No. It is a statutory right and the review is done by an appeals officer independent of the auditor who raised the assessment. Disagreeing through the proper channel is ordinary and expected.
For income tax, generally not while the objection or appeal is outstanding. Interest continues to accrue in the background, so if you lose it is waiting. Large corporations must pay 50% of the disputed amount, and trust amounts such as source deductions and GST/HST are treated differently.
Probably not. If you are correcting your own return rather than disputing the CRA's position, an adjustment request is faster and simpler. Objections are for disagreements, not omissions.
There is a separate process for disputing losses, because no tax, interest or penalty is involved and the ordinary objection route does not fit. Worth raising early if that is your situation.
This page describes the process in general terms as at August 2026 and is not advice for your situation. The CRA's guide P148, Resolving your dispute sets out objection and appeal rights under the Income Tax Act. Deadlines are statutory and unforgiving, so check yours against the notice in front of you.
Bring it to a twenty minute call. Often the first useful thing is simply working out which of the four routes you are on.
Call (905) 207-9639