How long do I have to object to a CRA reassessment?

Arsen Accounting Services · Question 107 · Sources checked October 29, 2026

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If you disagree with a reassessment, put the objection deadline on your calendar immediately. Calling CRA or sending documents for an informal review does not give you a safe reason to ignore the formal time limit.

The deadline depends on the taxpayer and assessment

For an individual other than a trust, or a graduated rate estate, CRA generally describes the income-tax objection deadline as the later of one year after the return's filing deadline and 90 days from the notice date. Other cases, including certain special assessments, use a 90-day limit. Corporations generally have 90 days.

An extension can sometimes be requested within one year after the missed objection deadline, but conditions apply. It is not an automatic extra year. Identify the assessment type before calculating the deadline.

Official guidance: [1].

Build the objection around the issue

A useful file explains what CRA changed, why you disagree, the amount in dispute, and the evidence supporting your position. For example, if CRA denied a deduction because documents were missing, organize the actual documents and explain how they meet the relevant conditions.

Keep the procedural records together

• The complete notice and its date.
• The return and schedules originally filed.
• Earlier review letters and responses.
• A concise statement of facts and the requested correction.

Record proof of submission. A complaint about service, a request for interest relief, and an objection to assessed tax serve different purposes. If several processes are relevant, identify each separately. Seek timely help where the amount or legal issue is significant, especially if you are near the deadline or already late.