What to take away
- A review is a check that a claim is correct and supported; it is a different process from a business audit.
- The CRA lists four examples of why a return is selected: a mismatch with third-party slips, the deductions or credits claimed, compliance history and random selection.
- Keep supporting records for at least six years, and reply to a review letter within the time frame it gives.
What the CRA actually does with your return
The CRA says it processes most returns without a manual review so that your notice of assessment can be issued quickly. It also says every return is screened by its computer system and may be reviewed at a later date, so a notice of assessment is not a clearance.
Paper and online filers go through the same selection process. The CRA also says it adjusts the focus of its reviews each year based on the results of earlier reviews and the areas where it sees non-compliance. In practice, that means the claims that attract attention can change from one year to the next.
The reasons a return may be selected
The CRA lists four examples. The first is a mismatch between your return and information it received from third parties, such as a T4 slip from an employer or a slip from a financial institution. The second is the type of deduction or credit you claimed. The third is your compliance history. The fourth is random selection.
The CRA does not publish its screening rules, so no one can tell you which claims are safe and which are not. Be cautious about any online advice that claims to know. What you can control is accuracy: report every slip you receive, claim only what you can support and keep the support organized.
Review programs and where they fit in time
The CRA describes several review programs. A pre-assessment review happens before your notice of assessment is issued, which can mean your notice or refund takes longer to arrive. A processing review is similar but happens after the notice has been issued. A request verification review happens when you ask the CRA to change a return, and it checks that the change is allowed and supported before a reassessment is issued.
A matching program compares what is on your return with information from sources such as employers and financial institutions. The CRA also lists a refund examination program, a supplementary examination program for income, losses and deductions that need closer study, a special assessments program and an identity protection program for suspected identity theft. As of April 2026, the CRA says it conducts processing reviews of individual returns on a year-round basis.
How a review differs from an audit
A review asks you to support specific amounts on a return, usually with documents sent to the CRA. A business audit is broader. The CRA describes it as a close examination of a business’s books and records to confirm that they support the amounts filed, and the auditor may look at business records, the owner’s personal records and records of related people or entities.
For businesses, the CRA says its risk-assessment systems identify returns considered high risk for non-compliance, and an officer then looks at information from various sources to decide whether an audit is needed. A business audit also has its own steps, a written summary of findings and a 30-day period to respond. This article stays with returns selected for review. If you have been told an audit is starting, speak with an accountant before you answer detailed questions.
What a review letter asks for
The CRA says it first tries to verify the claim using information it already has on file. It contacts you or your authorized representative by phone or in writing only if it needs more. Read the letter in full before doing anything else. Note the reference number in the upper right corner, the time frame to reply and the telephone number at the bottom.
Reply within the time given, quote the reference number and send the receipts or documents requested that apply to your situation. You or your representative can send scanned documents through a CRA account. If a receipt is missing, send a written explanation or call the number on the letter. Because the CRA may ask for items such as cancelled cheques or bank statements, a clean paper trail matters more than the form of any single receipt.
Keep records ready before you are asked
The CRA advises keeping income tax records, including receipts and documents that support your claims, for at least six years in case your return is selected. Support for different claims, such as a donation receipt, a medical invoice, a childcare receipt or a rental statement, tends to end up in different places, so it is easy to lose track of one years later.
A simple habit helps. When you file, save a copy of the return, the slips you received and one folder for each major claim, with a short note on how any estimate was worked out. Our article on how long to keep business records covers retention periods in more detail, and the digital receipts article explains what to store when you scan paper.
If the CRA changes your claim after a review
If a claim is changed after a review and you later find more information or documents, the CRA says it will accept new submissions and look at the claim again for a possible adjustment. Check the letter for how to send them. If you believe the CRA applied the rules wrongly to facts that are not in dispute, the route is different, and our article on disputing an assessment sets out objections and deadlines.
Do not ignore the letter. If the CRA does not receive what it asked for, it may have to decide the claim using only the information already on file, which can mean the claim is disallowed and a reassessment is issued. Asking for more time before the deadline is better than silence.
Using an accountant when a letter arrives
If you have authorized an accountant, the CRA may contact them instead of you. For processing review letters, the CRA says a representative receives them only if you authorized them and indicated on the return that the letters should go to them. Those letters can be viewed online in Represent a Client. Some programs send requests directly to the taxpayer even when a representative has been authorized, so watch your own mail too.
Bring the letter, the return as filed and the supporting records for the claim in question. Ask which claim is being reviewed, what proof fits it and whether any estimate needs to be explained. Our CRA audit support service helps with that preparation, and every situation depends on its facts.
Sources & editorial notes
Sources checked October 24, 2026. The examples are illustrative and provide general information. Discuss how the guidance applies to your circumstances with your accountant.
- How tax returns are selected for reviewCanada Revenue Agency
- Types of reviews: Review of your tax return by the CRACanada Revenue Agency
- Responding to us: Review of your tax return by the CRACanada Revenue Agency
- Business auditsCanada Revenue Agency
- EFILE news and program updatesCanada Revenue Agency
Rules and guidance can change. Use the current official source and confirm the treatment for your facts. To flag an error, contact Sora.