The agency says the seasonally adjusted annual rate fell to 192,928 units in October, down from 219,363 units in September.
The drop came as the seasonally adjusted annual rate of urban starts fell 12.1 per cent in October to 176,131 units.
Multiple-unit urban starts dropped 15.3 per cent to 115,402 units for the month, while single-detached urban starts slipped 5.4 per cent to 60,729 units.
CMHC says the annual pace of urban starts fell in British Columbia, Quebec, the Prairies, and in Atlantic Canada, but increased in Ontario.
Rural starts were estimated at a seasonally adjusted annual rate of 16,797 units.
The six-month moving average of the monthly seasonally adjusted annual rate stood at 199,920 units in October compared with 199,262 in September.
Canada Mortgage and Housing Corp. says the pace of housing starts in October slowed compared with September.