What Is an ITIN? A Canadian’s Guide to U.S. Tax Refunds

What Is an ITIN?

An ITIN — Individual Taxpayer Identification Number — is a nine-digit number issued by the IRS to people who need to file a U.S. tax return but are not eligible for a Social Security Number. For Canadians who had gambling winnings withheld at a U.S. casino, an ITIN is not optional. The IRS will not process your nonresident return — and will not issue your refund — without one.

If you have never filed a U.S. tax return before, you almost certainly do not have an ITIN yet. Nolly.com helps clients prepare and organize all the documentation required to apply for an ITIN and file successfully, connecting you with the right tax professionals at every step.

KEY TAKEAWAYS

• An ITIN is required before the IRS can process a U.S. nonresident tax return or issue a gambling tax refund.
• Canadians apply using IRS Form W-7, supported by certified identity documents.
• A Certified Acceptance Agent can verify your identity documents in-house, so you do not need to mail your original passport to the IRS.
• Once issued, an ITIN can be used for all future U.S. nonresident filings.

Why Do Canadians Need an ITIN?

Canadians need an ITIN because the IRS requires every person who files a U.S. tax return to have a taxpayer identification number, and non-residents who are not eligible for a Social Security Number must use an ITIN instead.

The most common reason a Canadian needs an ITIN is to claim a refund of the 30% withholding tax deducted from gambling winnings at a U.S. casino. Without an ITIN on your Form 1040-NR, the IRS cannot match your return to your identity and will reject or ignore the filing. This means the refund process cannot even begin until your ITIN is in place.

An ITIN is also used by Canadians who receive other types of U.S.-source income — such as rental income from U.S. property or certain investment distributions — and need to report it to the IRS. Once issued, the same ITIN is used for every future U.S. nonresident filing, so getting one is a one-time step.

What Form Do You Use to Apply?

You apply for an ITIN using IRS Form W-7, the official application for an IRS Individual Taxpayer Identification Number.

Form W-7 asks for basic personal information — your legal name, date of birth, country of citizenship, and foreign address — along with the reason you are applying. For most Canadians claiming a gambling tax refund, the reason is filing a U.S. nonresident return to recover withheld tax. The completed W-7 is typically submitted alongside your Form 1040-NR, not on its own.

What Documents Do You Need to Apply?

The IRS requires original identity documents — or certified copies — to verify your identity and foreign status when you apply for an ITIN. Accepted documents include:

• Passport (the only document that can be used on its own)
• National identification card (must show photo, name, address, date of birth, and expiry)
• Canadian driver’s licence
• Birth certificate (required for dependants under 18 if no passport is available)
• Foreign voter’s registration card
• Canadian military ID

For most Canadians, a passport is the simplest and most reliable option. The challenge is that the IRS originally required applicants to mail their original passport to a processing centre — a prospect most people understandably find uncomfortable. A Certified Acceptance Agent eliminates this requirement entirely.

What Is a Certified Acceptance Agent?

A Certified Acceptance Agent (CAA) is an individual or organization authorized by the IRS to verify identity documents on behalf of ITIN applicants, so the applicant does not have to send original documents to the IRS directly.

When you work with a CAA, they review your passport or other identity documents in person and complete a certification form that accompanies your W-7 application. The IRS accepts this certification in place of the original documents. For Canadians filing from outside the United States, this is a significant practical advantage — your identity is verified on a video call with a Certifying Acceptance Agent, so you don’t send your passport to the IRS.

This is one of the strongest reasons to work with a specialist rather than attempting to file on your own. Nolly.com connects clients with Certified Acceptance Agents and guides them through every stage of the documentation process, from gathering the right forms to ensuring everything is correctly organized before submission.

How Long Does It Take to Get an ITIN?

The IRS typically takes seven to eleven weeks to process an ITIN application when it is filed alongside a tax return. During peak filing periods — generally February through April — processing can take longer. If you apply outside of peak season, processing is often faster.

Because the ITIN must be in place before the IRS can issue a refund, delays in the ITIN application directly delay your refund. Starting the process early is the single most effective way to avoid unnecessary waiting. If you have a Form 1042-S from a U.S. casino, the time to act is now, not at the end of the tax year.

ITIN Application: At a Glance

Common Mistakes That Delay ITIN Applications

A small error on a W-7 application can result in rejection and restart the clock entirely. The most common problems include:

• Submitting uncertified photocopies of identity documents instead of originals or CAA-certified copies
• Leaving the “%reason for applying” field incomplete or selecting the wrong reason code
• Submitting the W-7 without the accompanying tax return (required in most cases)
• Name or date of birth on the W-7 not matching the identity document exactly
• Sending the package to the wrong IRS processing centre

Each of these errors results in a rejection letter and weeks of additional delay. Working with a specialist who prepares ITIN applications regularly is the most reliable way to get it right the first time. Nolly.com’s role is to help you arrive at the submission stage with a complete, correctly organized package — so there are no preventable surprises.

How Does the ITIN Connect to Your Gambling Tax Refund?

The ITIN is the thread that connects every part of the refund process. Once the IRS issues your ITIN, it is entered on your Form 1040-NR nonresident return, which is the document that formally claims back the tax withheld by the casino. The 1040-NR references your Form 1042-S — the casino’s record of what was withheld — and applies the relevant provisions of the Canada–U.S. Tax Treaty to calculate your refund.

Without the ITIN, none of this can proceed. With it, the IRS has everything it needs to identify you as the taxpayer, match the withholding records, and issue your refund. This is why obtaining an ITIN is always the first practical step in the refund process for Canadians who do not already have one.

Frequently Asked Questions

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Nolly.com is a private, independent platform and is not affiliated with any government agency. ITINs and EINs are issued solely by the Internal Revenue Service. Nolly.com assists clients in preparing and organizing documentation and does not issue, register, or approve any government identification number. This article is general information, not tax advice. Individual circumstances vary.

Published July 10, 2026. General information, not tax advice. Nolly Services Inc is a private company and is not part of the IRS.