Quick answer: A CRA pre-assessment review happens before a notice of assessment is issued, while a processing review happens after. Both ask for documents supporting a credit or deduction claimed on a return. The letter states the item, the deadline and the reference number. Sending complete records is what ends it.
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Key takeaways
- Pre-assessment reviews run before the notice of assessment; processing reviews run after.
- Selection can come from a mismatch with third-party slips, the claims made, compliance history or random pick.
- A pre-assessment review holds up your assessment, and any refund — until it is resolved.
- Records should be kept for at least six years in case a return is selected.
Two letters can look almost identical and mean slightly different things. Knowing which review program you are in tells you what is at stake and how quickly you need to move.
Pre-assessment vs processing review
The CRA runs several review programs. Two account for most of the letters small business owners see:
| Program | When it happens | What it means for you |
|---|---|---|
| Pre-assessment Review | Before the notice of assessment is issued | Your return is not assessed yet, so any refund is held until the review closes |
| Processing Review | After the notice of assessment has been issued | The return is already assessed; a change would come as a reassessment |
| Request Verification | Before a notice of reassessment is issued | The CRA is checking a change you asked for before making it |
| Matching | After the notice of assessment | Your return is being compared to slips filed by employers and payers |
The practical difference is timing and money. In a pre-assessment review the assessment itself is waiting, so a refund waits with it. In a processing review the money has usually already moved, and any adjustment comes back as a reassessment with a balance attached.
Why your return was picked
The CRA is explicit. A return may be selected because it does not match third-party information, because of the deductions or credits claimed, because of your compliance history, or at random. Paper and electronic returns are treated alike, and most are processed without manual review, but every return is screened and any can be reviewed later.
Random selection is worth sitting with for a moment. A review does not mean the CRA thinks something is wrong. It means a number needs support.
Every situation is different. Send an enquiry to a CPA and get a straight answer, plus a fixed quote before any work starts.
What to send
Send exactly what the letter names, and make it easy to follow. In practice that means:
- The reference number from the upper right corner of the letter on the first page of your package.
- The primary document for each item — the receipt, invoice, official slip or statement.
- Proof the money moved, where the claim depends on payment: a bank statement line or cancelled cheque.
- The calculation, where the claim is a percentage of something, such as a business-use share. A short note showing how you arrived at the figure is worth more than the raw records alone.
- A written explanation for anything you cannot produce, rather than a silent gap.
Documents can be uploaded online through My Account for individuals, or through My Business Account or Represent a Client where a corporation or an authorized representative is involved. Uploading is faster and creates a record of receipt.
If a claim is changed anyway
If the review changes your claim and you later find the documents, send them: the CRA accepts new submissions and will look again. Beyond that, the formal route is a notice of objection, with a deadline from the date of your notice.
Keep the records that make this short
The CRA asks you to keep income tax records and supporting documents for at least six years, so a shoebox fails when the letter concerns a year you have forgotten. See our guide to record retention and, for broader examinations, CRA reviews and audits.
The bottom line
Identify which review you are in, note the deadline, send the named documents with the reference number, and explain anything missing. If a claim depends on a percentage, send the working as well as the receipts. Keeping clean books year-round is what makes the whole exercise a short one.
This article is general information for Canadian business owners and is current as of July 2026. It is not tax, legal or accounting advice, and it does not create a client relationship. Tax rules change and your situation is unique, so please speak with a CPA before acting on anything here.
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Frequently asked questions about CRA Pre-Assessment Review: What to Send
What is a CRA pre-assessment review?+
How is a processing review different from a pre-assessment review?+
Why was my return selected for review?+
Does a pre-assessment review delay my refund?+
How long should I keep the supporting documents?+
Can I send more information after the review is finished?+
Under review and not sure what to send?
Forward the letter and its due date. A CPA replies by email within one business day with the documents needed and a fixed fee.
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