The national agency recorded 553 starts in November, compared with 928 in the same month last year.
At 289 starts, Ottawa single homes posted the best month in two years, stated Sandra Pérez Torres, CMHC's senior market analyst.
"New condo sales and building intentions have remained positive this year as they are supported by favourable financing conditions and underlying socioeconomic fundamentals," she added.
"Nevertheless, apartment construction posted a decline this past month, partly as a result of a comparison against last year's 25-year record high activity."
Year-to-date numbers were also below last year's pace, with 5,231 starts as of November. That was 11 per cent lower than the 5,904 recorded in November 2010.
Downtown Ottawa, as well as Nepean and Kanata, posted the greatest declines this month. The CMHC stated those areas had been the front-runners in activity at this time last year.
Single starts were most active in Cumberland, Nepean and Gloucester, with the latter area also leading in the townhome and apartment sectors.
Nationally, the seasonally adjusted annual rate of housing starts was 181,100 units in November, down from 208,800 in October.
Mathieu Laberge, deputy chief economist at CMHC's market analysis centre, said the decrease was due to a moderation in the multiples segment.
- With files from The Canadian Press