How to File a CRA Notice of Objection and Appeal

To file a CRA Notice of Objection, complete form T400A (or write a letter containing the same information), clearly identify the assessment and the specific errors you’re disputing, attach your supporting documents, and submit it to the Canada Revenue Agency within 90 days of the date on your Notice of Assessment. Individuals get extra time in many cases. Filing triggers an independent review by the CRA’s Appeals Branch, and if that review doesn’t fix the problem, you can take the dispute to the Tax Court of Canada.

The Filing Deadline

The Income Tax Act sets hard time limits, and they depend on who you are.

If you’re an individual (not a trust) or a graduated rate estate, you have the later of two dates: 90 days from the date on the Notice of Assessment, or one year after the filing deadline for the tax return in question.¹ That one-year alternative is useful when an assessment arrives well after you filed.

Corporations get 90 days from the date of the Notice of Assessment or Determination, with no one-year alternative. The same 90-day-only rule applies to trusts, RRSP and TFSA over-contribution assessments, and loss determinations.¹ Miss the deadline and the assessment becomes final.

If You’ve Missed the Deadline

You can ask the CRA for an extension of time to file, but only within one year after the original deadline expired.² That outer limit is absolute.

To have the extension granted, you need to show that during the original objection period you either couldn’t file (or couldn’t get someone to file for you) or genuinely intended to object. You also need to show you applied as soon as circumstances allowed and that granting the extension would be fair.¹ Spell out exactly why you were late and what got in the way. You can submit the extension application at the same time as the objection itself. If the CRA refuses, you can ask the Tax Court of Canada to grant the extension instead, subject to the same conditions and the same one-year outer boundary.

Valid Grounds for Objecting

A Notice of Objection isn’t a general complaint about your tax bill. You need to point to a specific error. Objections fall into two categories.

Factual disputes are the more straightforward type. The CRA may have mischaracterized a capital gain as business income, missed a deduction you claimed, or double-counted a source of income. Simple data-entry errors qualify too. If the numbers on your assessment don’t match what you reported and you can prove your version, that’s a factual objection.

Legal-interpretation disputes arise when you and the CRA read the same provision differently. A common example involves personal tax credits under Section 118 of the Income Tax Act, where the CRA might deny a spousal or dependant credit you believe you qualify for.³ Another frequent flashpoint is gross negligence penalties under subsection 163(2), where the CRA alleges you knowingly made a false statement or omission.⁴ Penalty objections are worth flagging because the CRA bears the burden of proving the facts that justify the penalty, not the other way around.

What to Put in the Objection

The standard form for an income tax objection is the T400A, “Notice of Objection – Income Tax Act.”⁵ The CRA also accepts objections by letter, but the form makes it harder to forget a required field.

Every submission needs:

Your social insurance number or business number
The tax year in question
The date of the assessment
Whether you’re disputing the entire assessment or specific items
A clear statement of reasons

The statement of reasons is the heart of the filing. Explain, specifically, what the CRA got wrong and why. “I disagree with my assessment” is not enough. Describe the disputed item, identify the factual or legal error, and reference the evidence you’re attaching. Receipts, bank statements, employment contracts, and prior CRA correspondence let the appeals officer work through your file without chasing you for more.

How to Submit It

You can file directly through CRA My Account using the “Register a formal dispute” option, which gives you an instant case number.⁶ Supporting documents can then be uploaded through the “Submit Documents” service. Tax representatives can do the same through the “Represent a Client” portal.

The CRA accepts common file types online, including PDF, Word, Excel, and image files, with a total upload limit of 500 MB for most programs and 1 GB for compliance and audit matters.⁷

For paper submissions, mail the completed T400A and supporting documents to the Appeals Intake Centre listed on your Notice of Assessment. Registered mail is worth the small extra cost because the delivery receipt proves you met the deadline.

What Happens After You File

Processing Times

The CRA assigns your file to an appeals officer for independent review. The officer may contact you for more documents or to discuss the legal merits. Timing depends heavily on complexity. As of February 2026, CRA processing times for income tax objections average about 125 days for low-complexity cases, 365 days for medium-complexity cases, and over 690 days for high-complexity files.⁸ GST/HST objections tend to move somewhat faster, averaging 115 days for simple disputes and over 500 days for complex ones.

If 90 days pass after you file and the CRA still hasn’t issued a decision, you don’t have to keep waiting. The Income Tax Act gives you the right to bypass the CRA and appeal directly to the Tax Court of Canada.⁹

Collections Are Paused, With Exceptions

Filing an objection puts a meaningful brake on CRA collection activity. While your objection is pending, the CRA generally cannot start legal proceedings, garnish your wages, or seize funds from your bank account to collect the disputed amount.¹⁰ Those restrictions stay in place until 90 days after the CRA sends its decision, and if you appeal to Tax Court, collection remains on hold until the court rules.

There are important exceptions. Payroll source deductions you were supposed to withhold and remit as an employer aren’t covered by the collection freeze. The CRA can also continue collecting from corporations that have filed objections, and for large corporations it can immediately pursue 50 percent of the assessed income tax even while the dispute is active.¹⁰

Interest Keeps Running

This catches most people off guard. Interest keeps accruing on the disputed amount for the entire duration of the objection and any subsequent appeal. The CRA doesn’t pause the interest clock just because you’ve challenged the assessment. If the process takes two years and you ultimately lose, you’ll owe the original tax plus two years of compound interest. If you win on some issues but lose on others, interest will have accumulated on whatever remains owing. Consider making a partial payment on any portion of the assessment you accept to limit the damage.

Extra Rules for Large Corporations

If your corporation qualifies as a “large corporation” under the Income Tax Act, the objection process has extra requirements that can cost you the right to raise issues later. The Notice of Objection must describe each issue in enough detail for the CRA to understand exactly what you’re disputing, specify the dollar amount of the change you’re seeking for each issue, and provide the facts and legal reasoning supporting your position on each issue.¹¹

This isn’t just a formality. A large corporation that fails to properly describe an issue in its objection can be barred from raising that issue on appeal to the Tax Court. If the CRA notices gaps, it may send a written request for the missing details, giving the corporation 60 days to respond, but relying on that safety net is risky.¹¹

If the Appeals Decision Still Isn’t Right

If the Appeals Branch confirms the original assessment or issues a reassessment you still disagree with, you have 90 days from the date the CRA mails that decision to file a notice of appeal with the Tax Court of Canada.¹² Miss that window and you can apply for an extension within one year, provided you show you intended to appeal, applied as soon as you could, have reasonable grounds, and that granting the extension would be fair.¹³

The Tax Court offers two tracks. The Informal Procedure covers disputes where federal tax and penalties at stake (not counting interest) are $25,000 or less per taxation year, or where the disputed loss is $50,000 or less.¹⁴ There’s no filing fee, the rules of evidence are relaxed, and you can represent yourself or use an accountant. The trade-off is limited appeal rights: a loss can only be taken to the Federal Court of Appeal on narrow grounds such as an error of law, a jurisdictional issue, or a factual finding made without regard for the evidence.¹⁵

Larger disputes fall under the General Procedure. Filing fees depend on the amount at stake: $250 for amounts under $50,000 (Class A), $400 for amounts between $50,000 and $150,000 (Class B), and $550 for amounts of $150,000 or more (Class C).¹⁶ The General Procedure involves formal discovery, stricter evidentiary rules, and a full trial, and most taxpayers hire a tax litigation lawyer.

Most disputes that resolve favorably resolve at the CRA Appeals stage, long before a courtroom is involved. That’s the reason to invest the effort in a thorough, well-documented objection at the start.

1
Canada Revenue Agency. Resolving Your Dispute: Objection Rights Under the Income Tax Act
2
Justice Laws Website. Income Tax Act – Section 166.1
3
Justice Laws Website. Income Tax Act – Section 118
4
Department of Justice Canada. Income Tax Act – Section 163
5
Canada Revenue Agency. T400A Notice of Objection – Income Tax Act
6
Canada Revenue Agency. Filing a Formal Dispute or Objection With the CRA
7
Canada Revenue Agency. Submit Documents Online
8
Canada Revenue Agency. Processing Times and Complexity Levels – Income Tax
9
Justice Laws Website. Income Tax Act – Section 169
10
Justice Laws Website. Income Tax Act – Section 225.1
11
Department of Justice Canada. Income Tax Act – Section 165
12
Tax Court of Canada. Frequently Asked Questions
13
Statutes.ca. Income Tax Act, Section 167
14
Tax Court of Canada. Get Started
15
Justice Laws Website. Federal Courts Act – Section 27
16
Justice Laws Website. Tax Court of Canada Rules (General Procedure) – Schedule