CRA & Revenu Québec

Where To Find Your Social Insurance Number, and What To Do If It’s Lost or Stolen

Your Social Insurance Number (SIN) is a 9-digit number provided to you from Service Canada. You need a SIN to work in Canada, have access to government benefits and programs, and it is your SIN that identifies you when you file your personal income taxes. If you’re a citizen, a permanent resident or a temporary resident, you need a Social Insurance Number (SIN).

Your parents may have applied for a SIN number on your behalf when you were born. Otherwise, you likely got your SIN as a teenager, before you started your first job.

Where Can I Find My Social Insurance Number (SIN)?

  • On your SIN card or confirmation letter: Service Canada used to issue SINs in plastic card format, however presently, they are issued in paper format. Check your records for either your card or confirmation letter.
  • On CRA documents: Your SIN is used to identify you with the Canada Revenue Agency (CRA) so you’ll find your SIN number on the first page of your tax returns and on any other documents or correspondence from the CRA.

Can I Get a Replacement If I’ve Lost my SIN?

  • To replace your lost SIN, you’ll need to visit your local Service Canada branch. If you visit with all the appropriate documents, Service Canada will give you your SIN number on the spot.
  • If you live more than 100 km from a Services Canada branch or cannot visit a Service Canada branch because of a special situation, you can make a SIN request by mail. But, before mailing your SIN request, you must first get permission from Service Canada by calling 1-800-206-7218 (select Option #3).
  • It’s important to note that you will only be issued a brand new SIN if you were the victim of identity theft or fraud. Check out Service Canada’s Protecting your Social Insurance Number web page for details.

Do I Have To Give Out My SIN?

You must give it to anyone who prepares information slips (such as T3, T4, or T5 slips) for you. Each time you do not give it when you are supposed to, you may have to pay a $100 penalty which is levied by the CRA. For this reason, it is important that if you receive any of these information slips that you check over the information on the slips, and if your SIN is missing or is incorrect, inform the slip preparer.

Your SIN is also used by the CRA when you make enquiries about your Income Tax, benefits such as the GST/HST Credit, Canada Child Benefit (CCB) and other Government programs such as Employment Insurance (EI), Canada Pension Plan (CPP), etc.

However, with the recent number of scams and fraudulent activity surrounding the CRA and identity theft, taxpayers should be vigilant when they receive, either by telephone, mail, text message or email, a fraudulent communication that claims to be from the Canada Revenue Agency (CRA) requesting personal information such as a Social Insurance Number. More information on recognizing a scam and protecting yourself against fraud can be found here

A complete list of “who can ask for your SIN”, as well as “when you don’t have to provide your SIN”, can be found in this CRA document.