CAN I FILE ONE RETURN FOR BOTH GST AND QST IN QUEBEC?

Business owners in Quebec often ask whether they need to file two separate sales tax returns one for GST and one for QST or if a single filing covers both. Fortunately, Quebec has one of the simplest systems in Canada when it comes to filing sales tax: Quebec businesses file a single combined return for both GST and QST. This guide explains how the combined filing works, which form to use, what rules apply, and how to ensure your filing is accurate and compliant.

Understanding Quebec’s combined filing system saves time, reduces errors, and ensures your business stays onside with Revenue Québec requirements.

LEGAL AND REGULATORY FRAMEWORK

Combined GST/QST filing is made possible through a tax administration agreement between:

• Canada Revenue Agency (CRA) responsible for GST
• Revenue Québec responsible for QST and GST administration within Quebec

Quebec administers both the federal GST and the provincial QST for businesses operating in the province. As a result, Quebec businesses file a single return using:

Form FPZ-500-V — GST/HST & QST Return

This form includes sections for:

• GST collected
• QST collected
• input tax credits (ITCs)
• input tax refunds (ITRs)
• adjustments
• the total net tax payable or refundable

KEY COURT DECISIONS

Courts confirm that:

• GST and QST are legally separate taxes
• but Quebec may administer GST filings on behalf of Canada
• businesses must comply with both laws when completing the combined return
• errors in the combined return can lead to adjustments for either tax base

The combined filing system does not merge the taxes legally — it only simplifies the reporting mechanism.

WHY THE COMBINED GST/QST RETURN EXISTS

The combined return is designed to:

• reduce administrative burden
• avoid duplicate reporting
• streamline refunds
• simplify audits
• improve compliance

Quebec is the only province in Canada where the federal GST return is filed through the provincial tax authority.

CAN YOU FILE ONE RETURN FOR BOTH GST AND QST? YES, HERE’S HOW IT WORKS

1. You file a single combined return (FPZ-500-V)

This return includes all the information required for both taxes.

2. You choose your filing frequency once (monthly, quarterly, annual)

The same frequency applies to both the GST and QST portions of your combined return.

3. You remit one payment

Payments for both GST and QST are made to Revenue Québec through:

• Mon Dossier online portal
• financial institution online banking
• pre-authorized debit
• mailed cheque (not recommended)

4. You receive one refund (if applicable)

Refunds for GST and QST are combined.
Revenue Québec may hold the refund if documentation is required.

5. You maintain two sets of tax numbers

You will still have:

• a GST number
• a QST number

But they are used together in one filing.

6. You must keep documentation for both taxes

Revenue Québec may request support for:

• GST-related ITCs (federal)
• QST-related ITRs (provincial)

WHEN YOU CANNOT USE THE COMBINED RETURN

There are rare exceptions, such as:

• non-residents operating under the Specified QST Registration System
• certain government entities
• organizations registered under specialized rules

Most Quebec-based businesses, however, file the FPZ-500-V.

COMMON MISTAKES WHEN FILING THE COMBINED RETURN

Businesses often make errors such as:

• mixing GST and QST amounts
• entering GST but forgetting QST
• misclassifying taxable vs. exempt sales
• applying GST and QST on different bases
• making manual overrides in accounting systems
• using old, incorrect form versions
• failing to reconcile GST/QST control accounts

These mistakes trigger verification or delay refunds.

BEST PRACTICES FOR FILING THE COMBINED RETURN

• use accounting software with correct GST/QST tax codes
• reconcile GST/QST collected monthly
• validate input tax credits/refunds with proper documentation
• maintain an audit-ready folder for each filing period
• double-check totals before submitting
• keep all invoices for six years
• monitor your refund status in Mon Dossier

MACKISEN STRATEGY

Mackisen CPA prepares and reviews combined GST/QST returns to ensure accuracy and full compliance. We reconcile tax accounts, detect mismatches, correct errors, and prepare audit-ready documentation. Our team also helps configure accounting systems so GST and QST codes feed correctly into your FPZ-500-V return.

REAL CLIENT EXPERIENCE

A Montreal retailer misclassified GST and QST in their POS system for months. Mackisen corrected the coding and cleaned up past filings.

A consultant forgot to include QST on taxable services, causing filing errors. Mackisen corrected the return and avoided penalties.

A startup repeatedly mixed-up ITC and ITRs. Mackisen rebuilt their documentation system and resolved ongoing refund delays.

COMMON QUESTIONS

Do I still have two tax numbers?
Yes, GST and QST are legally separate.

Do I file two returns?
No, one combined return.

Does the combined return apply to non-residents?
Usually no. Special QST rules may apply.

Where do I file?
With Revenue Québec through Mon Dossier.

WHY MACKISEN

With more than 35 years of combined CPA experience, Mackisen CPA Montreal ensures Quebec businesses file their GST/QST correctly and efficiently. Our compliance systems protect you from errors, delays, and audit exposure.