What to include in your notice of objection

The core requirement

The CRA’s instruction is plain: when you file an objection, you must clearly explain what you are objecting to and why you disagree with your assessment or determination, and include all relevant facts and supporting documentation. Form T400A, the paper objection form, puts it the same way: “Please state the issues, reasons and all relevant facts for your objection,” and include a copy of all relevant documents that support it. A short note saying “I disagree” does not meet that standard.

The CRA’s checklist

In its guide P148, the CRA lists the information to include with an objection:

• Your name and complete mailing address;
• A daytime telephone number;
• The date of the notice of assessment;
• The tax year;
• Your account number — social insurance number, business number, trust account number, or other account number;
• The relevant facts and reasons for your objection;
• Copies of all documents that support your objection; and
• Your representative’s name and address, if you have one.

The objection must also be signed and dated. If you file online through CRA’s “Register my formal dispute” service in My Account or My Business Account, the service walks you through its own fields and issues a case number; the facts, reasons and documents still have to come from you.

Organise it issue by issue

Most assessments turn on more than one point, and the CRA’s checklist points the same way: deal with each issue separately. For each issue, set out:

• What the CRA decided;
• Your facts — what actually happened, with dates and amounts;
• Your reasons — why you say the assessment is wrong on those facts;
• The change you are asking for; and
• The amount in dispute for that issue.

This per-issue structure is not just tidy — for large corporations it is a statutory requirement: ITA s.165(1.11) requires the objection to describe each issue, specify the relief sought for each issue, and provide the facts and reasons relied on for each one. Writing every objection this way keeps each point answerable on its own.

Gaps that weaken an objection

Measured against the CRA’s own list, the common gaps are omissions, not bad arguments:

• Leaving out the date of the notice. The CRA uses it to match your objection to the assessment; without it, processing can stall.
• One general complaint instead of issue-by-issue facts and reasons. An appeals officer cannot act on disagreement that never says which decision is wrong or why.
• No supporting documents. The instruction is to include copies of the documents that support your position — slips, invoices, receipts, correspondence — not to describe them and send them later.
• An unsigned objection. The CRA’s list ends with a signature and date; an unsigned paper objection may not be accepted as filed.

Keep a copy of everything

Whatever route you file by, keep originals and a complete copy of what you submitted, including the supporting documents, and note the date you sent it. If you filed online, keep the case number the service issued — it is the reference for submitting further documents on the same objection. If the CRA later asks what was in your objection, or a deadline question arises, that copy is your record.

How the Nyphron packet assembles this

Our packet is built around exactly this structure. It takes your answers issue by issue — what the CRA decided, your facts, your reasons, the change you want and the amount — and organises them into a facts-and-reasons letter, with an evidence checklist drawn from the CRA’s categories and a filing guide. It does not decide whether your assessment is wrong, and it does not file anything for you; it assembles what the CRA asks for, in the order it asks for it. For how and where to file, see how to file a notice of objection.

Check the official sources

Reviewed October 11, 2026. General information only; check the current instructions and your notice before filing.

• CRA P148: what information to include with your objection
• CRA: income-tax objections
• CRA: GST/HST objections