How do I appeal a CRA decision?

The first step is filing a Notice of Objection. You have 90 days from the date on your Notice of Assessment or Reassessment (the mail date, not the date you receive it). Submit Form T400A online through My Account, by mail to your Tax Services Office, or through a registered tax professional. Once filed, the objection goes to CRA Appeals — a separate division from the one that issued the reassessment — for an independent review.

What is the deadline to file a Notice of Objection?

Technically, you have the later of 90 days from the date on the Notice of Assessment (NOA), or one year from the due date of the return. For most people, the effective deadline is 90 days from the NOA date. Miss this deadline and CRA can and will reject the objection as out of time. You can apply for an extension up to one year later (bringing the outside limit to approximately 1 year and 90 days from the NOA date), but extensions are not guaranteed.

Do I need a lawyer or accountant to file an objection?

For a straightforward objection — a disallowed deduction with clear receipts — a CPA can help and the cost is modest. For complex objections involving large amounts, penalties, or legal interpretations of the Tax Act, a tax lawyer is advisable. If the objection is denied and you are headed to Tax Court, you will want a tax lawyer for the General Procedure. For the Informal Procedure (under $25,000), many people self-represent successfully.

What happens after I file a Notice of Objection?

CRA Appeals will confirm receipt and assign an Appeals Officer. The officer reviews the case independently (they are separate from Collections and Audits). They may contact you for more information, arrange a conference call to discuss the issues, and will ultimately issue a decision: allow the objection (decision in your favour), allow it in part, or confirm the reassessment. Objections typically take 12–36 months. While your objection is pending, collection action on the disputed amount is generally suspended.

What if CRA denies my objection?

If CRA denies your objection or confirms the reassessment, you can appeal to the Tax Court of Canada. You have 90 days from the date CRA notifies you of their objection decision. In Tax Court, you choose the Informal Procedure (for disputes under $25,000 in federal tax and penalties) or the General Procedure (mandatory for larger disputes). The Informal Procedure is designed for self-represented individuals and is relatively accessible.

How to Appeal a CRA Decision in Canada

If CRA has reassessed your tax return and increased your tax bill — and you believe the reassessment is wrong — you are not required to simply pay and move on. Canada’s tax system gives you the right to appeal, all the way to the Tax Court of Canada if necessary.

Here is the full process.

Step 1: Understand what you received

Before appealing, confirm what type of CRA document you have:

Notice of Assessment (NOA): Issued after you file your return. If it shows a different amount than what you calculated, CRA has changed something.
Notice of Reassessment (NOR): Issued after an audit or review. CRA has changed a previously accepted return.
Notice of Confirmation: Issued after you file a Notice of Objection. CRA reviewed your objection and is standing by its original position.

The 90-day appeal deadline starts from the date printed on the NOA or NOR — not the date you open it.

Step 2: File a Notice of Objection

Deadline

You have the later of:

90 days from the date on the original NOA or NOR, or
One year from the due date of the return in question

For most people, the binding deadline is the 90-day window.

Example: Your NOA is dated March 28, 2026. You have until June 26, 2026 to file.

If you miss the 90-day deadline, you can apply for a late-filing extension under Income Tax Act subsection 166.1 — but you must do so within one year and 90 days of the NOA date. Extensions are discretionary; do not count on them.

How to file

Option 1: CRA My Account (fastest)

Log in to My Account
Go to “Submit documents”
Select “Notice of Objection”
Describe the issue and upload supporting documents

Option 2: Form T400A (by mail)

Complete Form T400A (Notice of Objection) — available at canada.ca
Mail to the Chief of Appeals at your Tax Services Office (address is on your NOA)

Option 3: Your authorized representative A tax lawyer or CPA authorized on your My Account can file on your behalf.

What to include

Your Notice of Objection must clearly state:

Which line(s) you are disputing
The specific facts of your situation
Your argument for why CRA’s assessment is wrong
Supporting documents (receipts, contracts, correspondence)

A vague objection (“I disagree with the amount”) without specifics is harder to win. State the facts and attach the evidence.

Step 3: Wait for the Appeals review

Once your objection is filed, CRA Appeals — a division independent of the auditors who issued the reassessment — will:

Send an acknowledgment of your objection
Assign an Appeals Officer to your file
Review the file independently

The Appeals Officer may:

Contact you by phone to discuss the issues
Request additional documentation
Schedule a conference call with you and your representative

Timeline: Objections typically take 12–36 months depending on complexity and CRA’s backlogs. During this time, collection action on the disputed amount is generally held in abeyance (CRA will not pursue the amount under audit, though interest continues to accrue on amounts ultimately confirmed as owing).

Possible outcomes

Decision	Meaning
Allowed	CRA agrees with you — reassessment is cancelled or changed in your favour
Allowed in part	CRA partially agrees — some items accepted, others maintained
Confirmed	CRA stands by its original reassessment
Varied	The reassessment changes but not necessarily in your favour

Step 4: Tax Court of Canada (if objection is denied)

If CRA confirms the reassessment and you still disagree, your next step is the Tax Court of Canada. You have 90 days from the date of the Notice of Confirmation (or Varied) to file an appeal.

Two procedures

Informal Procedure

For disputes where federal tax and penalties total $25,000 or less (per tax year)
Faster, less formal, and designed for self-represented taxpayers
No formal pleadings required — you file a simple Notice of Appeal
Hearings are held in cities across Canada
Costs are modest — a filing fee of approximately $100
Many individuals win Informal Procedure cases without a lawyer

General Procedure

Required for disputes over $25,000 (or when you choose it for smaller amounts)
Formal litigation process — pleadings, examinations for discovery, legal arguments
Essentially requires a tax lawyer
The losing party may be ordered to pay the other side’s legal costs

Filing in Tax Court

File your appeal at: Tax Court of Canada, 200 Kent Street, Ottawa ON K1A 0M1, or through the online portal at tcc-cci.gc.ca.

You will need to file a Notice of Appeal that includes:

Your name, SIN, and address
The year(s) under dispute
A description of the assessment you are appealing
The facts and legal arguments you rely on
What relief you are requesting (reduce the assessment, cancel penalties, etc.)

Practical tips

Pay what is not in dispute. Interest continues to accrue on confirmed amounts. If part of a reassessment is clearly correct, paying that portion stops the interest clock on it.

Request loss of time extension early. If you think you might miss the 90-day deadline, file the Notice of Objection first (even a simple one) and supplement it with full details later. A timely filing preserves your rights; a late filing may not.

Get professional help early for large amounts. A tax lawyer’s fees on a $50,000 reassessment dispute are typically $5,000–$15,000 — often worth it if the reassessment is wrong. Wait until Tax Court and fees escalate significantly.

Keep all correspondence. Every letter from CRA has a date, a reference number, and often a direct phone number. These are your evidence trail.

How to Respond to a CRA Audit — Before the reassessment is issued
CRA Collections Explained — While your objection is pending, what CRA can and cannot do
How to Set Up a CRA Payment Plan — If you agree with part of the reassessment but cannot pay immediately
CRA Voluntary Disclosures Guide — If the reassessment uncovered unreported income