Insight
Nov 28, 2025
Mackisen
CHECKLIST: DOCUMENTS YOU NEED FOR A GST/QST AUDIT
When Revenue Québec or the CRA launches a GST/QST audit, the first thing the auditor will ask for is documentation. The strength of your documents determines whether your audit goes smoothly or turns into a stressful reassessment. Businesses that keep complete, well-organized records typically finish audits quickly with minimal adjustments. Those with missing invoices, incomplete descriptions, or inconsistent reports often face denied input tax credits, recalculated taxable sales, and interest or penalties. This guide provides a complete checklist of the documents you need for a GST/QST audit, helping your business stay compliant and fully prepared for review.
Understanding exactly what auditors look for helps you organize your files in advance. A GST/QST audit is primarily a documentation audit: the auditor verifies whether the numbers on your FPZ-500-V returns accurately reflect your books, invoices, receipts, and bank activity. This checklist ensures that every required document is available, complete, and easy to access.
LEGAL AND REGULATORY FRAMEWORK
Under the Excise Tax Act (GST) and the Quebec Taxation Act (QST), businesses must maintain complete records for at least six years. These records must support all amounts reported on GST/QST returns, including taxable sales, exempt sales, input tax credits, adjustments, refunds, and tax collected. Revenue Québec and CRA have the legal authority to examine books, records, and supporting documents to verify compliance.
Invoices must meet strict requirements: supplier name, address, GST/QST registration numbers, invoice date, description of goods or services, tax amounts, and total payable. If documents do not comply with these requirements, auditors may refuse input tax credits or recalculate your tax liability.
KEY COURT DECISIONS
Courts repeatedly affirm that taxpayers must produce proper documentation to support GST/QST filings. In numerous cases, taxpayers argued that expenses were legitimate but lacked compliant invoices. Judges upheld denials of input tax credits because the documentation did not meet the required legal standard.
Courts have also accepted the tax authorities’ use of indirect audit methods—such as bank deposit testing or sales projection analyses—when businesses did not maintain adequate records. The message from the courts is clear: proper documentation is the taxpayer’s responsibility.
WHY CRA AND REVENU QUÉBEC REQUEST THESE DOCUMENTS
Auditors request documents to verify three main areas:
Are taxable sales reported correctly?
Are input tax credits valid and supported?
Are adjustments, refunds, and write-offs documented?
Red flags that trigger document-heavy audits include inconsistent reporting, large refunds, missing POS summaries, unusual journal entries, incomplete invoicing, or discrepancies between GST/QST returns and financial statements. When documentation is organized and complete, the auditor’s work is straightforward, and the review often concludes faster.
GST/QST AUDIT DOCUMENTS CHECKLIST
Use this list to gather everything an auditor may request. Organize documents by period (monthly/quarterly) and by category.
GST/QST returns and assessments
FPZ-500-V returns for each period under audit
Notices of assessment and adjustment
Copies of any amended returns or correspondence with Revenue Québec
Financial statements and bookkeeping ledgers
Income statement and balance sheet for audit periods
General ledger, trial balance, and detailed tax accounts
Chart of accounts and tax code mapping
Sales documentation
All sales invoices with GST/QST amounts
POS summaries, Z-reports, end-of-day reports
E-commerce sales reports (Shopify, Amazon, WooCommerce)
Customer contracts and service agreements
Receipt books for manual or cash transactions
Credit notes issued for returns, discounts, and price adjustments
Purchase and expense documentation
Supplier invoices with GST/QST registration numbers
Receipts for all expenses related to input tax credits
Contracts, agreements, and purchase orders
Capital asset invoices (equipment, vehicles, improvements)
Subcontractor invoices and statements
Monthly vendor statements confirming balances
Bank records
Bank statements for each month in the audit period
Deposit slips and payment confirmations
Cancelled cheques and electronic transfer records
Merchant processor reports (Square, Moneris, Stripe, PayPal)
Supporting schedules and reconciliations
GST/QST collected vs. remitted reconciliation
Input tax credit summary schedules
Adjustments, write-offs, and bad debt schedules
Revenue reconciliations (bookkeeping vs. POS vs. bank deposits)
Accounts receivable and accounts payable aging reports
Payroll records (if applicable)
Payroll summaries showing taxable employer reimbursements
Employee expense reimbursements with GST/QST breakdown
Contractor payments and T4A/RL-1 slips if required
Inventory and cost of goods sold documentation
Inventory count reports
Purchase records supporting cost of goods sold
Import documents for cross-border purchases (CBSA forms)
Corporate legal documents
Articles of incorporation or business registration
Partnership or shareholder agreements
Leases and rental agreements for business premises
Special supply documentation
If you supply exempt, zero-rated, or partially taxable services or goods, include:
Classification memos
Supporting documentation for exemptions
Export documentation (for zero-rated exports)
Delivery evidence for on-reserve Indigenous exemptions
Communications with tax authorities
Letters, emails, and phone logs with CRA/Revenue Québec
Copies of any prior audit notices
Voluntary disclosure documents (if applicable)
Internal policies and accounting procedures
Invoicing procedures
Tax coding rules in accounting software
Refund and credit note procedures
POS tax configuration documentation
MACKISEN STRATEGY
Mackisen CPA prepares businesses for GST/QST audits by assembling complete documentation packages before the auditor arrives. We review invoices, reconcile GST/QST accounts, verify supplier tax numbers, and build audit-ready binders or digital folders. Our team identifies weak documentation areas early and helps businesses correct or replace incomplete records before submission.
During the audit, we manage communication with Revenue Québec or CRA, respond to document requests, explain discrepancies, and defend input tax credit claims. After the audit, we help implement stronger documentation controls to prevent future problems.
REAL CLIENT EXPERIENCE
A Montreal retailer faced a QST audit with missing supplier invoices and inconsistent POS summaries. Mackisen reconstructed missing documentation, contacted vendors for replacement invoices, and prepared a complete audit file. The auditor accepted all credits with minimal adjustments.
A construction company undergoing a GST/QST audit had incomplete subcontractor invoices and was at risk of losing significant input tax credits. Mackisen compiled proper support, added missing details, and prepared reconciliations that reduced adjustments substantially.
An online seller was audited after large QST refunds. Their Shopify reports did not match their accounting software. Mackisen aligned the data, reconciled differences, and presented clear evidence to the auditor. The refund was released.
COMMON QUESTIONS
What happens if I cannot find all the invoices the auditor requests
Missing invoices may lead to denied input tax credits. You should request duplicates from suppliers immediately.
Do auditors accept electronic documents
Yes. Revenue Québec accepts properly organized PDFs, digital exports, and accounting software reports.
How far back do I need documents
Typically six years, but longer if prior returns were not assessed or if fraud/misrepresentation is suspected.
Should I provide everything at once
Provide what the auditor requests, but in a fully organized way. A CPA can help manage the flow of documents.
Can I refuse to give certain documents
You can ask for clarifications, but legally, you must provide all records relevant to the audit.
WHY MACKISEN
With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps businesses prepare complete and compliant documentation for GST/QST audits. Our team ensures every document is aligned, organized, and ready to present, protecting you from reassessment and helping you navigate the audit process with confidence.
