CMHC is Canada's national housing agency, it plays a major role in housing finance, mortgage insurance and affordable housing programs across the Country.  It provides mortgage insurance to lenders when buyers make a down payment of less than 20% on a property.  This insurance protects the lender in the event the borrower defaults.  It also enables buyers to qualify for mortgages with smaller down payments.  There is a premium (typically added to the mortgage) paid for this insurance.