What is the Social Insurance Number (SIN) and how do I protect it from fraud?

✓ Verified answer Written from official pages, with checked citations and a verification date.

General information, not legal advice. The SIN is a 9-digit number you need to work in Canada or to access Government of Canada programs and benefits. It is confidential and it is illegal for anyone else to use it: it is up to you to protect it. Give it only when the law requires it, keep your documents in a safe place and be wary of messages claiming your SIN is compromised. If you suspect fraud, Service Canada says to file a police report, inform the Canadian Anti-Fraud Centre and monitor your credit file.

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Key facts

What the SIN is for: To work in Canada and to access Government of Canada programs and benefits (9-digit number).
Who to give it to: Only when the law requires it: employer (after hiring), financial institution (interest and dividend income), government services.
Not required for: A job application, a credit card, mortgage or rental application, most phone, Internet or cable subscriptions, renting a car.
Suspected fraud: Police report, Canadian Anti-Fraud Centre, credit reporting agencies, creditors and financial institutions. A new SIN is issued only if there is clear proof of fraud, and Service Canada does not advise it.
Getting or replacing a SIN: See the related page on getting and replacing a SIN.

Your procedure, step by step

Start the official procedure Official page: Protect your SIN (Service Canada) (opens in a new tab)https://www.canada.ca/fr/emploi-developpement-social/services/numero-assurance-sociale/protection.html

Give your SIN only when the law requires it, for example to an employer after you are hired, to a financial institution to report interest income or to a government service. Before giving it, ask yourself: is it required by law? Why is it needed? How will it be used? Who will have access?
Do not use your SIN as ID: your confirmation letter or SIN card are not identity documents. Offer your passport or driver's licence instead. You do not have to give your SIN for a job application, to rent a property or to sign up for phone or Internet services (except Hydro-Québec, which must collect it under provincial law).
Keep your SIN in a safe place: do not keep your confirmation letter or SIN card in your wallet or purse, store documents that contain your SIN in a locked cabinet or on password-protected devices, and shred them before disposing of them. To see your SIN, use My Service Canada Account.
Never give your SIN by phone unless you made the call and know the law requires it. Be wary of calls, texts or emails claiming your SIN is compromised, offering to replace it, threatening to lock or cancel it, or pressing you to act urgently. If in doubt, contact the organization directly.
Watch for signs of unauthorized use: a notice of reassessment from the Canada Revenue Agency for unreported income, credit applications you do not recognize in your credit report, or records of employment that are not yours in My Service Canada Account.
If you are a victim of fraud: file a police report and keep the reference number, inform the Canadian Anti-Fraud Centre, contact the two main credit reporting agencies (TransUnion Canada and Equifax Canada) and consider a fraud alert, then notify your creditors and your financial institutions.
If your SIN was used to obtain money from a government program (for example employment insurance), report the fraud directly to that program. Service Canada states that you do not have to report SIN fraud to the SIN program and that a new SIN is not advised: it does not erase the old one and does not protect against future abuse.
For the details, the documents to provide and the contact information, see the official Service Canada pages (Protect your SIN; SIN fraud and data breaches).

Your progress is kept on this device only: nothing is sent to Demande au Québec. Some steps only apply in certain situations: skip the ones that do not concern you.

General information drawn from official sources. It does not replace legal, medical or financial advice. For your situation, contact the organization concerned or a professional.

Sources

Numéro d’assurance sociale (NAS) (Service Canada (Emploi et Développement social Canada))
Protégez votre NAS (Service Canada (Emploi et Développement social Canada))
Fraude de NAS et fuites de données (Service Canada (Emploi et Développement social Canada))

Checked on October 6, 2026. Rules, deadlines and fees can change: always confirm on the official page above. Demande au Québec is an independent website, not a government site.

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