Notice of Objection (T400A): Deadlines, Steps, Timelines

If you disagree with a Canada Revenue Agency (CRA) assessment or reassessment, you have the right to file a Notice of Objection. Acting quickly matters: strict timelines apply, and missing them can cost you your appeal rights. This guide explains who can object, exact deadlines, how to file online or by form T400A, what happens next, and how our tax lawyers at KR Law Firm can help.

What Is a Notice of Objection?

A Notice of Objection asks CRA’s independent Appeals branch to review an assessment or determination. It is the formal first step in disputing CRA’s decision under the Income Tax Act. You can object to personal, corporate, or trust assessments, as well as certain determinations (for example, loss determinations). See CRA’s guide P148 – Resolving your dispute.

Who Can Object?

• Individuals (T1), including the self-employed.
• Corporations (T2) and trusts.
• Other statutes: for GST/HST objections use GST159 – Notice of Objection (GST/HST). (In Quebec for GST/HST administered by Revenu Québec, see FP-159-V.)

Deadlines: 90 Days (and the 1-Year Rule for Individuals/GREs)

Timelines are strict:

• Individuals (other than trusts) and Graduated Rate Estates (GREs): the later of 90 days from the date CRA mailed the notice or 1 year after your filing due date for that year (see P148 and Register my formal dispute).
• All others (e.g., corporations, most trusts): generally 90 days from the mailing date of the notice (P148).
• Missed your deadline? Apply for an extension of time under ITA s.166.1 within one year after the objection due date. If CRA refuses, you may apply to the Tax Court within 90 days (s.166.2).

How to File: Online or by Form T400A

Option 1 — File Online (Fastest)

• Log in to My Account or My Business Account and use “Register my formal dispute” (CRA link).
• Attach a PDF of your objection letter and supporting documents.

Option 2 — Mail Form T400A

• Download T400A – Notice of Objection (Income Tax Act) and complete all fields.
• Include a detailed statement of facts, issues in dispute, and relief requested; attach copies of the assessment/reassessment and evidence.
• Mail to the address indicated on the form or P148 instructions. Keep copies and proof of mailing.

What to Say in Your Objection (and What to Attach)

• Identify the assessment(s): tax year(s), amounts in dispute, date of notice.
• State the issues clearly: e.g., business expenses denied, capital vs. income treatment, source deductions, credits.
• Explain your position: concise facts and legal basis (cite receipts, contracts, logs, slips, accounting records).
• Attach supporting documents: bank/credit statements, invoices, mileage logs, T-slips, prior correspondence.

What Happens After You File

• Appeals review: a CRA Appeals officer independently reviews your file, may request more information, and can confirm, vary, or vacate the assessment.
• Collections while you object: CRA generally restricts collection of income tax amounts in dispute during an objection, but collections can continue for certain debts (e.g., GST/HST net tax, source deductions). See CRA collections policy IC98-1.
• If CRA confirms the assessment: you may appeal to the Tax Court of Canada within the prescribed time.

Missed the Deadline? Extension of Time (s.166.1 ITA)

If you miss the objection deadline, you can apply to CRA for an extension of time. Key points:

• Apply within one year after the original objection deadline.
• Explain why you missed the deadline, show that you intended to object, and that it is just and equitable to grant the extension.
• If CRA refuses (or does not respond within 90 days), you may apply to the Tax Court of Canada within 90 days (s.166.2 ITA).

How KR Law Firm Can Help

• Assess your case, deadlines, and best filing method (online vs. T400A).
• Draft a precise objection with evidence, legal analysis, and requested relief.
• Communicate with CRA Appeals, manage additional requests, and negotiate outcomes.
• Escalate to Tax Court or pursue Taxpayer Relief (RC4288) where penalties/interest are unfair.
• Advise on collections exposure during the objection and strategies to mitigate risk.

Need help now? Contact KR Law Firm or book a FREE consultation with one of our tax lawyers.

FAQs

What is the deadline to file a Notice of Objection?

Generally 90 days from the date CRA mailed your notice. For individuals (other than trusts) and GREs, it’s the later of 90 days or 1 year after the filing due date (see P148).

How do I file an objection?

Either online using “Register my formal dispute” in My Account/My Business Account (CRA link) or by mailing Form T400A.

Will CRA stop collections while I object?

For income tax amounts in dispute, CRA generally delays collections during an objection; however, collections can continue for certain debts like GST/HST net tax and source deductions. See IC98-1.

What if I miss the objection deadline?

Apply for an extension of time (s.166.1 ITA) within one year of the missed deadline. If CRA refuses, you can apply to the Tax Court within 90 days (s.166.2).

Do I need a tax lawyer?

It’s not mandatory, but legal representation helps ensure your arguments are properly framed, deadlines are met, evidence is organized, and your rights are protected.

Call to Action

If you’ve received a Notice of Assessment and disagree, don’t wait. KR Law Firm represents clients nationwide in objections and appeals. Book a FREE consultation with a tax lawyer today.