When you retire, your retirement income will come from three sources.

Government-sponsored pension plans
When you retire, you may be entitled to receive pension benefits from the following government-sponsored pension plans:
Canada Pension Plan (CPP)
CPP provides you with a basic retirement income. It replaces a portion of your employment earnings (up to the YMPE) on which you made contributions, with the standard replacement rate being approximately 25% for older participants and gradually increasing due to CPP enhancements. CPP is paid monthly until death and is adjusted each January 1st to reflect increases in the cost of living. The CPP pension is taxable income.
The PSSP is designed to work with CPP.
Old Age Security (OAS)
The OAS pension is a monthly payment available to most Canadians 65 years of age who meet the Canadian legal status and residence requirements. You must apply to receive it. In addition to the OAS pension, there is the Guaranteed Income Supplement (GIS).
Guaranteed Income Supplement (GIS)
If you live in Canada and you have a low income, GIS is a monthly non-taxable benefit that can be added to your OAS pension.
To learn more about these government-sponsored pension plans, please visit the Service Canada website: www.servicecanada.gc.ca