Canadians are used to being asked for their Social Insurance Number as a piece of identification, but the Canadian Social Insurance Number is a confidential number and an important piece of personal information. Your Social Insurance Number can be used, in combination with other pieces of personal information, to monitor many of your daily activities or steal your identity, so it should be treated carefully. Here are the basics on when and how to use your Canadian Social Insurance Number.

The Canadian Social Insurance Number - or SIN - is a unique nine-digit client account number used by the federal government in Canada to administer specific government programs. It was originally created to be used for the administration of the Canada Pension Plan and unemployment insurance programs, but is now also used for tax purposes and a variety of other income-related purposes.

Basically, you need a Social Insurance Number to work in Canada, to file your income taxes and to receive federal government benefits, such as the Old Age Security Pension. Only specific government departments and programs are authorized to collect and use your Social Insurance Number. Other organizations are also required by legislation to use the Social Insurance Number for income-related purposes, for example banks.

You are required to give your Social Insurance Number

• for insurable or pensionable employment in Canada. You are required by law to show your employer your Social Insurance Card within three days of the start date of employment.
• to file your income taxes. You must give your Social Insurance Number to any organization which prepares income tax information for you. This includes federal, provincial and municipal agencies which report financial assistance payments for income tax purposes.
• to organizations where you earn interest or income, such as banks, credit unions, or stock brokers.
• to authorized federal government departments and agencies.

Human Resources and Development Canada has a complete list of Legislated Uses of the Social Insurance Number in Canada.

Many other organizations, both inside and outside government, have found that using the Social Insurance Number is an easy way to organize their own accounts. While there is no legislation authorizing them to do so, there is also no legislation preventing them.

However, your Social Insurance Number is a confidential number and should not be used for general purposes of identification.

The Office of the Privacy Commissioner of Canada recommends that if you are asked for your Social Insurance Number:

• ask if it is required by law
• ask what it will be used for
• if your Social Insurance Number is not required by law, offer to provide another piece of identification
• if your Social Insurance Number is not required by law and the organization refuses service unless you provide it, then file a complaint with the Office of the Privacy Commissioner of Canada.