What to Write in Your Notice of Objection: Facts and Reasons in Canada

A notice of objection is your chance to tell the CRA why an assessment is wrong. Many objections are weakened not by the merits but by thin explanations, missing documents or missing details. The law asks for reasons and facts, and the CRA expects them in a particular form.

This article walks through what to include, how to organize your reasons, and the common traps. It is general information, and a lawyer or accountant can help with the specifics of your file.

This article covers Canadian federal tax law, which applies in every province.

What the law requires

A taxpayer who objects to an assessment must serve a written notice of objection setting out the reasons for the objection and all relevant facts. Two words matter: reasons and facts. A statement such as "I disagree" gives the CRA nothing to review.

Larger corporations have a stricter standard. A large corporation's notice must reasonably describe each issue, state the relief sought for each issue as a change in a balance or undeducted amount, and give facts and reasons for each issue. If information is missing, the Minister may request it and the corporation has 60 days to provide it.

Details to include

CRA lists what the notice should contain:

• Your name, complete mailing address and daytime phone number.
• The notice date and the tax year.
• Your SIN, business number or other account number.
• The relevant facts and reasons, with copies of supporting documents.
• The representative's name and address, if you have one.
• Your signature and the date, with an authorized officer signing for a corporation or trust.

Check that the notice date is correct. Objection deadlines run from the day the notice of assessment was sent, not the day it was received.

Organizing your facts and reasons

Think of the facts as what happened and the reasons as why the assessment is wrong given those facts. A clear structure helps the appeals officer follow your position.

• Identify each item you dispute, such as a disallowed deduction, a credit or a penalty.
• State the facts for each item in order, with dates and amounts.
• Explain why you say the assessment is incorrect and what result you want.
• Refer to each attached document by name so the officer can match it to your point.

Penalties and interest are part of the assessment, so the objection can dispute them. Asking the CRA to cancel or waive them as a matter of fairness is a separate request, not an objection.

Common traps

• Holding back information. If you withheld information during an audit or in response to a CRA request and give it only with your objection, the file may be sent back for a second review.
• Objecting to something that cannot be objected to. Examples include statements of account, auditor's proposal letters, RRSP or TFSA room statements, carryforward balances and nil assessments.
• Objecting too early or too late. Objections filed late or before the notice was issued may be invalid.
• Objecting to an issue you waived in writing. You cannot object to it, and you cannot appeal it to the Tax Court.

Filing it and what to do next

You can file online through My Account for Individuals or My Business Account by selecting "Register my formal dispute", and you receive a case number. A representative can use Represent a Client. You can also mail or fax a signed letter to the Chief of Appeals or deliver it in person. CRA says portal submissions are assigned to an appeals officer sooner than paper.

If you use a form, note that Form T400A was cancelled as of 2026-10-26 and replaced by Form RC592, Notice of Objection. RC592 is a fillable PDF that must be downloaded and opened in Acrobat Reader 10 or later, not in a web browser.

• Confirm the objection deadline for your situation.
• List every item you dispute and the facts behind each.
• Gather and label supporting documents.
• Sign and date the notice.
• Keep your case number and use it on all later correspondence.
• Have a lawyer or accountant review the draft if the amount is significant.

Frequently asked questions