Social insurance number (SIN)

As an employer, you have to ask your employees for their social insurance number (SIN) within three days of when they start to work for you and record their number.

Under the Department of Employment and Social Development Act, an employee who does not have a SIN when they start working for you has to apply for one and give it to you within three days after they receive it. As an employer, you must inform Service Canada within six days of your employee starting to work for you that this individual did not give you their SIN. If your employee needs a SIN, refer them to their Service Canada Centre to find out how to get one.


An eligible person who is not a Canadian citizen or a permanent resident of Canada and who applies for a SIN will get a SIN beginning with the number "9."

Make sure the employee gives you their correct name and SIN. You may ask for other types of identification, such as a birth certificate or a certificate of citizenship or permanent residence, before finalizing their employment documents. An incorrect SIN can affect an employee’s future Canada Pension Plan benefits if their record of earnings is not accurate. Also, if you report an incorrect SIN on a T4 slip that has a pension adjustment amount, the employee may receive an inaccurate registered retirement savings plan (RRSP) deduction limit statement and the related information on the employee’s notice of assessment will be inaccurate.

What if the employee refuses to give you their SIN or to apply for one?

If an employee does not give you their SIN, you must be able to show that you made a reasonable effort to get it.


An example of a reasonable effort would be if, after asking your employee for their SIN many times, you decide to contact them in writing to request his SIN. Make note of the dates you asked for the SIN verbally, and keep copies of any written requests.

If you do not make a reasonable effort to get a SIN, you may have to pay a penalty.

Even if you have not received your employee's SIN, you have to make deductions and remit them, and file your T4 information return on or before the last day of February of the following calendar year. If you don't, you might get a penalty for remitting or filing late.

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