In Canada, a Social Insurance Number (SIN) is a 9-digit number that is required to work and be paid in Canada, as well as to access government programs and benefits. It is also used to file taxes. The SIN is issued by Service Canada, a Canadian government department, and is private and confidential. It is illegal for anyone else to use it, and individuals are responsible for protecting their SIN.

To apply for a SIN, individuals must provide a valid original primary document to prove their identity and legal status in Canada, such as a Work Permit or Study Permit issued by Immigration, Refugees and Citizenship Canada (IRCC), as well as a valid original secondary document to confirm their identity, such as a passport or provincial or territorial ID card or driver’s license. SINs have nine digits displayed in three groups of three, and Canadians must update their SIN record if they change their name due to marriage or other circumstances.

If an individual forgets their SIN, they can find it on their income tax return, tax slips, record of employment, RRSP contribution, or view it by signing in or registering for My Service Canada Account (MSCA), or obtain a confirmation of their SIN by submitting an application. If an individual loses their SIN or if it was stolen, Service Canada will not issue a new one unless there is proof that the SIN was used fraudulently.

It is important to note that a Canadian Social Insurance Number is not a valid Taxpayer Identification Number (TIN) for the purposes of U.S. tax reporting and withholding regimes.