CRA Notice of Objection: How to File One and What to Expect

A notice of objection is the formal instrument for disputing a CRA assessment or reassessment. It is not a phone call, not a complaint, and not a letter to your MP. It is a statutory right under section 165 of the Income Tax Act, and filing one triggers a formal review by the CRA’s Appeals division, which operates independently from the auditor or reviewer who issued the assessment. Roughly 128,000 taxpayers filed one in 2024-25. The CRA agreed with the taxpayer, in full or in part, about 55% of the time over a seven-year average. If you are not sure whether you received a reassessment or something else, start with what a CRA reassessment is and how to respond. This page is the objection mechanics.

What is the deadline for filing a notice of objection?

For individuals (not trusts or corporations), the deadline is the later of two dates: 90 days after the day the notice of assessment was sent, or one year after the taxpayer’s filing-due date for that year (section 165(1)(a)). For corporations and trusts, the deadline is strictly 90 days after the day the notice was sent (section 165(1)(b)). The filing-due date for most individuals is April 30 of the year following the tax year. So if the CRA reassesses your 2024 return in June 2025, your deadline is the later of 90 days from the reassessment notice (roughly September 2025) or April 30, 2026 (one year after the 2024 filing-due date). The one-year rule gives individuals more time than they realize on recent-year assessments.

The date the notice was “sent” is the date printed on the notice of assessment, not the date you received it. If you were travelling and did not open the envelope for three weeks, those three weeks still count against the 90 days. For non-residents who may receive CRA mail late (international post, forwarding delays), this is a real risk.

What if I missed the deadline?

Two routes. First, section 166.1 lets you apply to the CRA for an extension of up to one additional year beyond the original deadline. The CRA may grant it if you demonstrate that you intended to object within the deadline and were unable to do so for reasons beyond your control. Second, if the CRA refuses the extension, section 166.2 lets you apply directly to the Tax Court of Canada for an order extending the time. Neither route works if more than one year has passed since the original deadline expired. After that, the assessment stands.

For cross-border filers, the missed-deadline risk is elevated. If you emigrated from Canada and your CRA address was not updated, the notice of assessment may have gone to an old address. The CRA’s obligation is to send the notice, not to ensure you received it. Update your CRA address before you leave, and keep My Account access active for exactly this reason.

How do I actually file the objection?

Three methods: through My Account online (the fastest), by mailing or faxing Form T400A (Notice of Objection Under the Income Tax Act) to the Chief of Appeals at your tax centre, or by sending a letter that covers the same statutory requirements. The statute requires only that the objection be “in writing, setting out the reasons for the objection and all relevant facts” (section 165(1)). There is no filing fee.

What to include in the objection:

1. Your name, SIN, and the taxation year(s) you are disputing.
2. The specific items on the assessment you disagree with (line numbers, amounts).
3. The reasons you believe the assessment is wrong, with references to the relevant provisions of the Act or treaty where possible.
4. The facts that support your position, including any documents you can attach (receipts, contracts, foreign tax returns, T-slips, correspondence).
5. The relief you are requesting (the specific dollar change you believe is correct).

A one-line objection that says “I disagree with the reassessment” is technically valid but practically useless. The CRA Appeals officer who reviews your file needs enough detail to understand the dispute without having to guess. The more specific and documented the objection, the faster the review.

What happens after I file?

The CRA’s Appeals division takes over the file. The Appeals officer is independent from the auditor or program area that issued the assessment. They review your objection, may request additional information, and can interview you or your representative. The review can result in three outcomes: the CRA allows the objection (in full or in part and issues a new assessment), the CRA partially allows it (adjusting some items but not others), or the CRA denies it and issues a Notice of Confirmation.

Current processing times vary by complexity. The CRA’s own reporting breaks objections into three tiers: approximately 125 days for low-complexity cases, 365 days for medium-complexity, and 896 days for high-complexity. Cross-border cases (treaty claims, foreign tax credits, departure-tax disputes) typically fall into the medium-to-high range.

Interest continues to accrue on the disputed amount during the entire review period under section 161. Even if the CRA ultimately agrees with you, the interest that accumulated does not automatically disappear. You may need to file a separate taxpayer relief request on Form RC4288 to have interest waived for CRA-caused delays.

Collection activity is generally suspended while the objection is pending, which is critical if the CRA has already started garnishing wages or freezing accounts. Section 225.1 prevents the CRA from taking collection action (garnishment, bank freezes, requirements to pay) on the disputed amounts until 90 days after the Notice of Confirmation is sent, or until any Tax Court appeal is resolved. This protection covers only the amounts under objection; undisputed amounts for other years remain collectible.

What are the real success rates?

About 55% of objections result in a full or partial change in the taxpayer’s favour, based on the CRA’s published data averaged over seven years. That headline number includes everything from complete reversals to minor concessions on one issue out of five. It does not mean you have a coin flip; the success rate depends heavily on the issue.

Objections on documentary matters (a credit was disallowed because the CRA did not receive supporting documents, and you have them) tend to resolve quickly and favourably. Objections on characterization disputes (business income vs. capital gains, employee vs. contractor, resident vs. non-resident) are more complex and often proceed to Tax Court if the CRA and the taxpayer disagree on the law. Objections on foreign tax credits and treaty claims for cross-border filers fall somewhere in between: the law is usually clear, but the CRA may dispute the foreign tax calculation or the treaty article that applies.

The 55% figure is also affected by strategic withdrawals: some objections are filed as protective measures while the taxpayer gathers evidence, and the taxpayer may later concede on weak issues while pressing strong ones. The CRA’s reported statistics count any change as a “taxpayer-favourable” outcome, even if the change is minor.

What if the CRA denies my objection?

The CRA issues a Notice of Confirmation. You then have 90 days to file a Notice of Appeal with the Tax Court of Canada under section 169(1). You can also file directly with the Tax Court if the CRA has not responded to your objection within 90 days, without waiting for a decision.

The Tax Court offers two procedures. The Informal Procedure is available when the federal tax and penalties in dispute total $25,000 or less per year, or when the only issue is a loss determination up to $50,000. It is faster, less formal, and does not require a lawyer (though representation helps). The General Procedure applies to amounts above those thresholds and follows standard court rules.

In both procedures, the taxpayer bears the burden of proof on most factual issues. The exception is penalties: the CRA must establish the facts justifying a penalty (section 163(3)). For cases involving a transfer pricing adjustment or certain other ministerial assumptions, the burden may shift to the Minister under section 152(4.01).

Should I hire someone for the objection?

The objection itself does not require professional representation. Many taxpayers file on their own, and the Informal Procedure at Tax Court is specifically designed for self-represented taxpayers. But two situations make professional help worth the cost: complex cross-border disputes (where the interaction between Canadian and US tax, treaty claims, and foreign tax credits creates layered issues), and high-dollar disputes where the stakes justify the investment.

If someone else is filing on your behalf, the CRA needs an active authorization: either a current Represent a Client authorization or a signed Form T1013 submitted with the objection. Without it, the CRA will not discuss your file with your representative.

How does an objection affect my US return?

If you are a cross-border filer (US citizen or green card holder with Canadian filing obligations), a Canadian reassessment changes your US foreign tax credit calculation. The treaty’s Article XXIV allows a credit for Canadian tax paid, so any increase or decrease in Canadian tax directly affects the US credit. While the objection is pending, file a protective claim (Form 1040-X or a letter to the IRS preserving your right to amend) on the corresponding US year before its statute of limitations expires.

If the CRA ultimately reduces the Canadian tax, your US foreign tax credit was overstated and the IRS may have a claim against you for the difference. If the CRA increases the Canadian tax (in a case where you objected a reassessment that was partially favourable), the additional US credit may produce a US refund. Either way, do not wait for the Canadian outcome to think about the US side. The reassessment response guide covers the cross-border coordination in more detail.

What should I do next?

Check the date on the notice of assessment. Count 90 days from that date (or check the one-year-from-filing-due-date rule if you are an individual). Gather the documents that support your position. Draft the objection with specific facts, reasons, and the relief you are requesting. File through My Account, mail, or fax. Then file a protective claim on the US return if applicable. For data on which types of objections actually succeed (and which do not), see CRA appeal outcomes by issue type.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.