High Quality Content by WIKIPEDIA articles! A social insurance number (SIN) is a number issued in Canada to administer various government programs. The SIN was created in 1964 to serve as a client account number in the administration of the Canada Pension Plan and Canada`s varied employment insurance programs. In 1967, Revenue Canada (now the Canada Revenue Agency) started using the SIN for tax reporting purposes. SINs are issued by Human Resources and Social Development Canada (previously Human Resources Development Canada).