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To dispute a CRA assessment, you file a notice of objection. For most individuals the deadline is the later of one year after the return’s filing deadline or 90 days after the date on the notice. You can file in My Account, by mail or by fax, and interest keeps running on the disputed amount until the CRA decides.
When does a notice of objection make sense?
You can object to a notice of assessment, reassessment, determination or redetermination. That includes notices about benefits and credits such as the Canada Groceries and Essentials Benefit, the Canada child benefit and the disability tax credit. You cannot object to a statement of account or an auditor’s proposal letter, and you have to wait until the notice actually arrives. If your return shows a loss, ask for a loss determination first and object to that notice.
Check the faster routes before you object. The Canada Revenue Agency: Income tax objection decision tree page says it can be quicker, for an individual return, to wait for the CRA to finish an adjustment request, and you can change your return instead of objecting. Penalties and interest go through a separate request, covered in our taxpayer relief article.
What is the deadline to file?
| Who or what | Deadline |
|---|---|
| Individuals and graduated rate estates (most assessments) | The later of one year after the return’s filing deadline (30 April, or 15 June if self-employed) or 90 days after the notice date |
| RRSP or TFSA over-contribution assessments, and loss determinations | 90 days after the notice date |
| Corporations | 90 days after the notice date |
| Trusts (T3) | The later of one year after the T3 filing deadline or 90 days after the notice date |
If you miss the date, you can ask for an extension. The Canada Revenue Agency: Publication P148, Resolving your dispute says to apply as soon as possible and no later than one year after the objection was due. You have to show that you could not object, or meant to, that an extension is fair, and that you applied promptly. You can send the request with your objection. If the extension is refused, or not decided within 90 days, you can apply to the Tax Court of Canada.
Here are two cases, using our own day count. A notice of assessment dated 12 May 2026 for the 2025 return (filing deadline 30 April 2026) gives a deadline of 30 April 2027, because one year after the filing deadline is later than 90 days after the notice (10 August 2026). A reassessment dated 20 October 2026 for the 2023 return is different: one year after that filing deadline passed in April 2025, so the 90-day count applies and ends on 18 January 2027. Check any date against the wording on your own notice.
How do you file a notice of objection?
- Online: sign in to My Account (or My Business Account) and choose “Register my formal dispute”. You get a case number to put on later documents. Representatives use Represent a Client. The CRA says portal filing gets your objection assigned sooner.
- By mail or fax: send the CRA’s objection form, or a signed letter with your facts and reasons, to the Chief of Appeals at the Appeals Intake Centre in Sudbury, Ontario.
- In person: deliver it to a tax services office or tax centre.
On the form, the Canada Revenue Agency: Form T400A page says T400A was cancelled as of 26 October 2026 and replaced with Form RC592, Notice of Objection. The Canada Revenue Agency: File an income tax objection page still named T400A when we opened it on 31 October 2026, so use the form the CRA links that day or send the signed letter.
What should the objection include?
- Your name, complete mailing address and a daytime phone number
- The date of the notice of assessment and the tax year
- Your SIN, business number, trust account number or other account number
- The facts and the reasons you disagree, with copies of supporting documents
- Your representative’s name and address, if you have one
- Your signature and the date
Send a separate objection for each assessment, unless the facts and reasons are identical. Information you did not give during an audit may be sent back to the area that issued the decision for a second look, so give it up front.
What happens after you file?
The Appeals Branch reviews the file and may contact you or your representative. If it agrees in whole or in part, it issues a reassessment or redetermination. If it disagrees, it issues a notice confirming the original assessment. The CRA gives no fixed number of days. Its Canada Revenue Agency: Check CRA processing times page, updated 20 October 2026, calls the time a target that depends on complexity (low, medium or high), and time you take to send more information is not counted. You can phone an Appeals Intake Centre for status.
Do you have to pay while the objection is open?
You generally do not have to pay disputed income tax until the review is complete, but interest still accrues. Paying all or part of the amount stops further interest on that part. Amounts you were required to withhold and remit must be paid on time, and in gifting tax shelter (charitable donation) cases you must pay half of the disputed amount.
After the decision, you pay what is no longer in dispute, and collection is usually delayed 90 days after the decision is sent. If you paid disputed amounts and have no decision after 120 days, you can ask for a refund (half the amount for charitable donation objections). If you cannot pay in full, see what to do when you can’t pay the CRA.
What if you still disagree with the decision?
You can appeal to the Tax Court of Canada. The Court must receive your notice of appeal within 90 days of the date the CRA sends its decision, and you can also appeal if the CRA has not decided within 90 days of your objection. Collection is normally postponed until the Court mails its decision or you withdraw. Further appeals go to the Federal Court of Appeal (30 days after the Tax Court’s final judgment) and then the Supreme Court of Canada (60 days for a leave application), as publication P148 describes. To understand the notice you are objecting to, start with our notice of reassessment guide.
What could change?
Two things moved recently. The objection form changed on 26 October 2026, and the CRA’s processing-time page was updated on 20 October 2026. Both can change again, so confirm the current form and timing on the CRA pages before you file.
Where does this information come from?
Rules come from the Canada Revenue Agency pages File an income tax objection, the objection decision tree, publication P148 Resolving your dispute, the Form T400A and RC592 pages, and Check CRA processing times. Checked on 31 October 2026. This is an independent information site: we provide no services, we do not represent the CRA or any organization, we collect information from open sources, and we do not guarantee that anything here is accurate or current. We accept no liability for decisions based on it. Check the official source before you rely on it. See the full disclaimer.
Frequently asked questions
How long do I have to file a notice of objection with the CRA?
For most individuals it is the later of one year after the return filing deadline or 90 days after the date on the notice of assessment. RRSP or TFSA over-contribution assessments and loss determinations get 90 days, and corporations get 90 days from the notice date.
How do I file a notice of objection?
Sign in to My Account, choose "Register my formal dispute" and you get a case number. You can also mail or fax the CRA objection form or a signed letter with your facts and reasons to the Chief of Appeals at the Appeals Intake Centre, or deliver it to a tax services office.
Do I have to pay the tax while my objection is being reviewed?
Generally not for disputed income tax until the review is complete, but interest still accrues, and paying all or part of the amount stops further interest on that part. Amounts you were required to withhold and remit must still be paid on time.
How long does the CRA take to decide an objection?
The CRA gives no fixed number of days. Its processing-time page says the targeted time depends on complexity (low, medium or high) and that time you take to provide more information is not counted. You can phone an Appeals Intake Centre to ask about the status.
What can I do if the CRA confirms the assessment?
You can appeal to the Tax Court of Canada. The Court must receive your notice of appeal within 90 days of the date the CRA sends its decision. You can also appeal if the CRA has not decided within 90 days of your objection.
- Dealing with the CRA: letters, audits and payments
Dealing with the CRA: what to do when a letter arrives, how a review differs from an audit, how My Account helps, and what to do if you can't pay