Quick answer: A CRA GST/HST review or audit letter asks you to support information in a return, such as sales, tax collected or input tax credits. First confirm that the contact is genuine, read which reporting periods and records CRA wants, and note the response date on your letter. A review is not necessarily a full audit.
What this means: You may be asked for a few receipts or for broader books and records. The steps and deadlines change as the file progresses: a preliminary audit-adjustment statement has a 30-day discussion period, while a GST/HST assessment or reassessment has a separate 90-day formal objection period.
What to do next: Check your CRA business-account correspondence and CRA’s business-audit instructions. Gather only the requested periods, ask how to submit records securely, and keep a copy of everything you send.
Review, examination or audit: read the notice first
CRA uses different processes for GST/HST returns. A post-assessment review may ask you to explain an amount or provide receipts after a return has been filed. CRA says this is different from an audit. Refund claims may also receive a pre-assessment examination before payment. A GST/HST audit examines records more broadly to check the return and the tax collected or credits claimed.
Do not assume that a request for documents means CRA has decided you owe tax. The CRA after-filing guide explains post-assessment reviews, while its GST/HST audit page explains audit and examination selection. Your own letter or account notice tells you which process and reporting periods apply.
Confirm the CRA contact is genuine
CRA says an auditor will usually make contact by phone and send a letter confirming the audit details. You do not need to hand over records during an unexpected call before you are satisfied that the caller is from CRA. CRA says you can call the auditor or team leader back, or wait for the confirmation letter.
Use CRA’s official contact information or the business-account correspondence to check a suspicious request. Keep any personal, business and banking details out of an unverified email or call. This step is about confirming the request, not delaying a real deadline: if the date on a genuine letter is near, contact CRA promptly to clarify it.
Make a one-page request checklist
Once the contact is confirmed, write down the GST/HST reporting periods, the tax issue, the exact records requested, the submission method, the named CRA contact and the date by which CRA wants a response. The first letter’s date is case-specific. Do not substitute a generic “30-day rule” for whatever CRA actually wrote to you.
If the scope is unclear, ask the CRA officer to explain it before sending a large unrelated file. If you need more time to gather records, raise that with the officer before the stated date rather than letting it pass without a reply. Keep notes of the conversation and copies of any written follow-up.
Gather the records that match the question
CRA’s GST/HST record-keeping guide says business records must be detailed enough to calculate tax collected and amounts claimed. If you claimed an input tax credit (ITC)—a credit for eligible GST/HST paid on business purchases—keep the purchase invoice or receipt that supports it. A bank withdrawal alone may not show the details needed for an ITC.
Depending on what the letter asks for, your packet may include:
- Filed GST/HST returns and any adjustments for the named periods.
- Sales invoices, receipts or other records showing what you sold and the GST/HST collected.
- Purchase invoices and receipts that support the ITCs on those returns.
- Ledgers, contracts or bank records that help reconcile the amounts, if requested.
Sort documents by reporting period and label what each document supports. CRA’s ITC information requirements explain why an invoice needs more than just an amount. Do not assume every purchase is eligible for an ITC merely because a receipt shows GST/HST.
Send records using a secure route
CRA’s audit guidance says its auditors cannot receive files by email for security reasons. Use CRA’s secure online document service, deliver documents through an accepted CRA office route, or use the mailing instructions supplied by the officer. Confirm the method for your file before sending private records.
Keep copies of the documents and a record of when and how you sent them. If an officer borrows original records during an audit, CRA says the auditor provides a detailed receipt. Avoid sending extra tax years or unrelated personal records just because they happen to be in the same folder; respond to the actual request and ask if the scope changes.
What happens after the records are reviewed?
Some files close without a change. If a GST/HST audit finds proposed adjustments, CRA’s registrant guide RC4022 says you receive a preliminary statement and have 30 days to analyze and discuss it with the auditor. That is the time to point out a missing invoice, an arithmetic error or a misunderstood transaction and provide supporting records.
After that stage, CRA may issue a notice of assessment or reassessment. The notice states the results and any change to the return. Review the notice itself, not just a phone conversation, before deciding whether you accept it or wish to dispute it.
If you disagree: the GST/HST objection is a separate step
For GST/HST, CRA’s RC4022 guide gives 90 days from the date on the notice of assessment or reassessment to file a formal objection. It points to Form GST159, Notice of Objection (GST/HST), and also describes the online “File a formal dispute” service in My Business Account or Represent a Client.
The 30 days to discuss preliminary findings and the 90 days to object to an issued notice are not interchangeable. Form GST159 is the GST/HST form; do not substitute an income-tax objection form. If the disputed amount or issue is substantial or the notice is difficult to interpret, professional advice may help you assess the options, but the official notice date still matters.
Example: a disputed input tax credit
Imagine a business gets a letter asking for purchase invoices supporting an ITC on one quarterly GST/HST return. It checks the request, gathers the invoices for that quarter and sends them by the secure method CRA provides. If CRA later proposes removing one ITC, the business compares the preliminary statement with its invoice and explains the difference during the 30-day discussion window. If CRA still issues a reassessment and the business disagrees, the 90-day GST/HST objection period begins on the date of that notice.
This is a process illustration only. It does not assume the ITC is valid or predict CRA’s decision. The evidence and the law for the actual purchase control the result.
Common mistakes
- Assuming every GST/HST document request is a full audit. Read the stated process and scope.
- Sending financial records by ordinary email. Use the secure route CRA provides.
- Missing the date on the first letter. The response date is specific to the file.
- Using a bank statement instead of an invoice for an ITC. CRA requires supporting purchase documentation.
- Mixing up the two later time periods. Preliminary discussion is 30 days; a formal GST/HST objection after a notice is 90 days.
Frequently asked questions
- Does a post-assessment review mean a full GST/HST audit?
- No. CRA describes a post-assessment review as different from an audit. It may ask for an explanation or supporting documents for specific amounts.
- How long does a GST/HST audit take?
- CRA says the time varies. It does not publish one duration for every business audit. The scope, records available and follow-up questions all matter.
- Can I email the auditor my invoices?
- CRA says auditors cannot receive files by email. Ask for the secure submission route for your case.
- Which GST/HST objection form do I use?
- CRA identifies Form GST159 for an objection to a GST/HST assessment or reassessment. The formal dispute can also be submitted through the applicable CRA account service.
- When does the 90-day objection period begin?
- It runs from the date on the GST/HST notice of assessment or reassessment, not from the first review letter or preliminary discussion statement.
Rules and process basis
This article covers CRA’s public GST/HST review, audit and objection procedures checked September 24, 2026. It does not decide whether a business owes tax, qualifies for an ITC or should object. The first-letter response date and requested records are case-specific; the 30-day preliminary discussion period and 90-day formal objection period arise at different later stages. Use the actual CRA correspondence and official sources below for your file.