The short version
- A notice of objection is the formal way to dispute a CRA assessment or reassessment. It's free, you don't need a lawyer, and it goes to an appeals officer who wasn't part of the original decision.
- Individuals have until the later of one year after the return's filing due date and 90 days after the notice. Corporations and GST/HST disputes have 90 days.
- File online in My Account or My Business Account ("Register my formal dispute"), or on form T400A (income tax) or GST159 (GST/HST) by mail.
- For income tax, CRA generally doesn't collect the disputed amount while you object, but interest keeps running. GST/HST and payroll amounts can still be collected.
- If you still disagree after CRA's decision, you can appeal to the Tax Court of Canada within 90 days. Its informal procedure has no filing fee for income tax disputes up to $25,000 of federal tax and penalties a year.
CRA Notice of Objection: Complete Guide
Disagreeing with CRA isn't rude, and it isn't hopeless. Many objections end with CRA changing its mind, in full or in part, often because the person finally sent the document that made the case. The trick is to file on time, say exactly what's wrong and why, and prove it. Angry letters don't move appeals officers. Receipts do.
Before You Object: Is There a Faster Fix?
| Situation | Better route |
|---|---|
| CRA denied a claim because you didn't send receipts | Send them to the review area with the reference number; see CRA review letter |
| You made a mistake on your own return | Change it in My Account (ReFILE or Change my return); see changing your return |
| You want penalties or interest cancelled for reasons like illness or CRA delay | A taxpayer relief request, not an objection |
| CRA got the law or the facts wrong, and the deadline is approaching | File the objection. You can send the documents too |
When in doubt and the deadline is near, file the objection. It protects your rights; a phone call doesn't.
Deadlines
| Who or what | Last day to object |
|---|---|
| Individuals (T1) and graduated rate estates | The later of one year after the filing due date (April 30, or June 15 for self-employed) and 90 days after the date on the notice |
| Corporations (T2) | 90 days after the notice |
| GST/HST | 90 days after the notice |
| Missed it | Ask for an extension within one year after the deadline |
Work out your exact date with the objection deadline calculator. If it's close or already gone, see objection deadline rules for the extension of time.
Draft your objection properly, on time
The SmartFile reads your notice, works out your deadline, sorts what you agree and disagree with, and drafts the statement of facts and reasons for form T400A or My Account. You check and sign.
What to Put in It
- Identification: name, SIN or business number, the tax year and the date of the notice you're objecting to.
- Each issue: one line per change you dispute, such as "denial of $8,400 of rental expenses."
- The facts: what actually happened, briefly and in order.
- The reasons: why CRA's change is wrong under the rules. Quote the CRA guide or folio if one supports you.
- The relief you want: the amount you say it should be.
- Supporting documents, or a list of what you'll send.
Object to each year separately. Large corporations must describe every issue and the relief sought with specific amounts, or the objection can be invalid; for everyone else, clear is enough.
How to File
- Online: My Account (individuals), My Business Account (businesses) or Represent a Client: "Register my formal dispute." Fastest, and you get a confirmation.
- By mail: form T400A for income tax, GST159 for GST/HST, or a signed letter with the same information, to the address on the form.
- Keep proof of the date you filed.
While Your Objection Is Open
- Collection: for income tax, CRA generally holds off collecting the disputed amount until 90 days after its decision. Large corporations must pay half. GST/HST and payroll deductions can be collected anyway.
- Interest keeps running on any amount you end up owing. Paying the disputed amount stops it, and CRA refunds it with interest if you win. See late payment interest.
- Benefits and refunds from other years may be applied against the balance.
- Timeline: CRA's 2026-27 goal is to resolve low-complexity objections within 180 days and medium-complexity ones within 365 days. You can send more information any time.
The Decision and What Comes After
| Outcome | Next step |
|---|---|
| Allowed (CRA agrees) | Reassessment in your favour, with refund interest |
| Allowed in part | Reassessment; appeal what's left if you still disagree |
| Confirmed (CRA disagrees) | Appeal to the Tax Court of Canada within 90 days |
| No decision yet | You can appeal after 90 days (income tax) or 180 days (GST/HST) from filing the objection |
The Tax Court's informal procedure is meant for people without lawyers: no filing fee, for income tax disputes up to $25,000 of federal tax and penalties per year (or $50,000 of losses) and GST/HST disputes up to $50,000. Above that, the general procedure has fees of $250 to $550, and corporations need a lawyer.
Common Mistakes
- Missing the deadline because you were waiting for CRA to call back.
- Objecting with no facts: "I disagree" is not a reason.
- Not paying anything on a large balance you're likely to lose, and letting interest compound.
- Signing a waiver in an audit settlement without noticing it gives up the right to object on those issues.
- Using an objection for relief from penalties because of hardship; that's a different request.
Read your notice first: notice of reassessment or notice of assessment. The rest of dealing with CRA is on the CRA guide.
CRA Objection Questions
How do I file a notice of objection with CRA?
Online through My Account, My Business Account or Represent a Client using Register my formal dispute, or by mail on form T400A for income tax or GST159 for GST/HST.
What is the deadline to object to a CRA reassessment?
For individuals, the later of one year after the return’s filing due date and 90 days after the date on the notice. For corporations and GST/HST, 90 days after the notice.
Do I have to pay while my objection is being reviewed?
For income tax, CRA generally does not collect the disputed amount while the objection is open, but interest continues. GST/HST and payroll amounts can be collected. Large corporations must pay half.
Do I need a lawyer to object?
No. Anyone can file an objection. For large amounts, penalties or complex issues, a tax professional is often worth it.
What if CRA rejects my objection?
You can appeal to the Tax Court of Canada within 90 days after the notice of confirmation. The informal procedure has no filing fee for income tax disputes up to $25,000 of federal tax and penalties per year.
Sources: CRA, Income tax objections decision tree; File an appeal to the Court; GST/HST Memorandum 31-0, Objections and appeals; Tax Court of Canada, Get started. Checked October 2026. The collection rules for large corporations and the 90-day hold on collection are from the Income Tax Act as we understand them. Objection processing times vary; CRA publishes current estimates on its processing times page.
Last reviewed October 5, 2026 against CRA and Government of Canada sources. How we check our facts.