HomeTax InsightsCRA Objection in Canada 2025: How to Dispute a Tax Assessment Using Form T400A
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CRA Objection in Canada 2025: How to Dispute a Tax Assessment Using Form T400A

Swift Ltd — Calgary Tax Specialists June 2026 8 min read 2025 CRA

Receiving a Notice of Assessment or Notice of Reassessment that you believe is wrong is a stressful experience. The good news is that Canada's tax system gives every taxpayer a formal legal mechanism to challenge CRA's decisions: the Notice of Objection. This guide walks you through the full CRA objection process in 2025, from understanding when to file to what happens if your case proceeds to Tax Court of Canada.

When to File a CRA Objection

A CRA objection is a formal legal dispute of a decision made by the Canada Revenue Agency. You have the right to file one when you disagree with a Notice of Assessment (NOA) or Notice of Reassessment (NOR) because:

  • CRA made an error in calculating your tax owing
  • CRA disallowed a deduction or credit you are entitled to claim
  • CRA included income you do not believe should be subject to tax
  • A credit, loss carryforward, or other adjustment was applied incorrectly

An objection is not simply a request to revisit your file — it is a statutory right under the Income Tax Act (ITA), and it triggers a formal review process that is separate and independent from the CRA division that originally assessed you. Filing an objection is also a legal prerequisite before you can appeal to Tax Court of Canada, which means skipping this step forfeits your right to judicial review.

The 90-Day Deadline

Timing is critical. Under the ITA, you must file your Notice of Objection within the later of:

  • 90 days from the date printed on the Notice of Assessment or Reassessment, or
  • One year from the filing deadline for the tax year in question (typically April 30 for individuals, or June 15 for the self-employed, though tax owing is still due April 30)

For example, if CRA reassesses your 2023 personal return and the notice is dated March 1, 2025, you have until May 30, 2025 (90 days) to file, or until April 30, 2025 (one year from your 2023 filing deadline) — whichever is later. In this case, May 30 gives you more time.

Missing the deadline is serious. CRA may reject your objection as out of time, and you would lose your right to dispute the assessment through this channel. CRA does have authority to grant a late-filing extension under subsection 166.1 of the ITA, but extensions are not guaranteed and require you to demonstrate that you were unable to act within the deadline or that it is just and equitable to grant the extension. Do not rely on an extension being approved — act as early as possible.

Form T400A and Online Filing

A Notice of Objection can be filed in two ways:

  • Paper Form T400A: Available from the CRA website or by calling CRA. Mail it to the Chief of Appeals at your regional CRA Tax Centre.
  • Online through CRA My Account: Use the "Dispute your assessment" service under the "Tax returns" section. This is the fastest method and creates an immediate timestamp on your submission.

Whichever method you use, your objection must include:

  • Your full legal name and Social Insurance Number (SIN)
  • The specific assessment being disputed, including its date and the applicable tax year
  • A clear statement of the reasons for the objection
  • Each issue identified separately (do not bundle multiple disputes into one vague paragraph)
  • The specific change you are requesting and the factual or legal basis for it

What to Include in a Strong Objection

The strength of your objection often determines the outcome. A vague statement that you "disagree with the assessment" is rarely successful. A well-constructed objection should include:

  • Specific legal grounds: Reference the relevant sections of the Income Tax Act where CRA misapplied the law. For instance, if your home office deduction was disallowed, cite the applicable subsection and explain why you meet the qualifying conditions.
  • Supporting documentation: Receipts, invoices, contracts, bank statements, employment agreements, lease agreements, or any records that corroborate your position. Documents submitted at this stage are part of the official record.
  • A corrected calculation: Show clearly what you believe the correct tax figure should be, line by line. This makes it easier for the Appeals Officer to evaluate your position.
  • Professional advice received: If an accountant, tax lawyer, or advisor guided your original filing, noting this can help demonstrate that the tax treatment was considered and deliberate rather than careless.
  • CRA's error: Articulate specifically where CRA went wrong — whether it mischaracterised a transaction, applied the wrong provision, or failed to account for a document you had provided during an audit.

At Swift Accounting Calgary, we prepare objections that are legally grounded and document-rich. The difference between a generic objection and a precise, well-supported one can be the difference between a full reassessment in your favour and years of further dispute.

The CRA Appeals Process

Once your Notice of Objection is received, CRA assigns it to an Appeals Officer within the Appeals Division — a branch that is independent from the Auditing Division that issued your assessment. This separation is important: the Appeals Officer is not defending the auditor's original decision. They are conducting a fresh review (de novo) of the file.

The Appeals Officer may:

  • Contact you or your representative for additional information or clarification
  • Request further documentation
  • Propose a settlement or partial resolution
  • Issue a decision based on the existing file

Processing times vary significantly. Straightforward objections involving a single disallowed deduction may resolve within 60 to 90 days. Complex business disputes, transfer pricing matters, or cases with large amounts at issue can take anywhere from 6 to 24 months. CRA's Appeals backlog has grown in recent years, so patience — and proactive follow-up — is important.

Possible Outcomes of Your Objection

After the Appeals Officer completes their review, one of four outcomes is possible:

  • Objection allowed: CRA agrees with your position entirely and issues a reassessment reducing or eliminating the tax owing. Any overpayment is refunded with interest.
  • Objection partially allowed: Some issues are resolved in your favour, others are not. A partial reassessment is issued accordingly.
  • Objection confirmed: CRA maintains its original assessment. At this point, your next option is to appeal to Tax Court of Canada.
  • Settlement offered: In some cases, CRA may propose a negotiated compromise — particularly in cases involving grey-area issues or where litigation risk exists for both parties. You are not obligated to accept.

Tax Court of Canada: Your Next Step

If CRA confirms the assessment after your objection, you have 90 days from the date of the confirmation to file an appeal with Tax Court of Canada. There are two procedures:

  • Informal Procedure: Available when the total federal tax and penalties in dispute is $25,000 or less, or where losses in dispute are $50,000 or less. The process is less formal, rules of evidence are relaxed, and you can represent yourself. Decisions are generally faster.
  • General Procedure: For larger amounts, this is a full court proceeding governed by the Tax Court of Canada Rules. Legal representation is strongly advised, and the process resembles civil litigation.

Tax Court is genuinely independent of CRA and has the authority to overturn CRA assessments entirely. While going to court is a significant step, taxpayers do win — particularly when supported by thorough preparation and strong documentation.

Do You Have to Pay While You Object?

Generally, CRA does not enforce collection of the disputed amount during the objection period or while a Tax Court appeal is pending. This is an important protection — it means you typically will not face garnishments or liens on the amount under dispute while your case works through the process.

However, interest continues to accrue on any unpaid tax balance throughout this period. If you ultimately lose your objection, you will owe the original tax plus all accrued interest. For this reason, some taxpayers choose to voluntarily pay the disputed amount to stop interest from running, and then request a refund if the objection is successful. CRA will refund the overpayment with applicable interest if you prevail.

If you are facing a significant balance and are unsure whether to pay now or hold, a tax professional can help you model both scenarios and make an informed decision.

Get Professional Help With Your CRA Objection

Navigating a CRA objection without professional support is possible, but the stakes are high and the procedural requirements are strict. A missed deadline, a vague submission, or missing documentation can undermine an otherwise valid dispute. The team at Swift Accounting in Calgary has experience preparing and managing CRA objections across a range of issues — from disallowed business expenses and rental losses to unreported income disputes and GST/HST assessments.

If you have received a Notice of Assessment or Reassessment that you believe is incorrect, act quickly. The sooner you engage professional support, the more time you have to build a strong objection.

Contact Swift Accounting today to speak with a Calgary tax professional about your CRA objection — we will assess your situation, explain your options, and help you respond with the strongest possible case.


Frequently Asked Questions: CRA Objection Canada

How long does a CRA objection take to resolve?

Processing times depend on the complexity of your case. Simple objections involving a single issue may be resolved in 60 to 90 days. More complex matters — multi-year disputes, business deductions, or cases requiring significant document review — can take 6 to 24 months. CRA's Appeals Division has faced increasing workloads in recent years, so delays beyond CRA's own service standards are common. Staying in contact with your assigned Appeals Officer and responding promptly to any information requests can help avoid unnecessary delays.

Can I file a CRA objection if I filed my taxes late?

Yes, filing your return late does not eliminate your right to object to an assessment. The 90-day objection deadline runs from the date on the Notice of Assessment, regardless of when you filed. However, if you also want to use the "one year from the filing deadline" window, note that this is calculated from your statutory filing deadline (typically April 30), not the date you actually filed. If in doubt about your specific deadline, calculate both dates and use the later one — then confirm with a tax professional.

What happens if CRA denies my objection?

If CRA issues a Notice of Confirmation upholding the original assessment, you have 90 days from the date of that confirmation to appeal to Tax Court of Canada. For amounts of $25,000 or less in federal tax (or $50,000 or less in losses), the Informal Procedure offers a less formal, lower-cost path where self-representation is practical. For larger amounts, the General Procedure applies and legal representation is strongly recommended. Importantly, the objection stage is a legal prerequisite — you cannot go directly to Tax Court without first having filed and received a response on your objection.

Does filing a CRA objection stop CRA from collecting the debt?

Yes, for the disputed amount only. CRA is generally required to hold collection action on the amount under dispute from the time a valid objection is filed until 90 days after the objection is resolved (or until a Tax Court appeal is decided, if you proceed that far). This means CRA cannot garnish wages or seize accounts for the objected amount during this period. However, interest on unpaid tax continues to accrue throughout. Any undisputed portion of a balance — for example, if only part of the assessment is being challenged — remains subject to normal collection. If you receive collection calls during an active objection, document them and raise the issue with CRA directly or through your tax representative.

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