Canada's seasonally adjusted Ivey purchasing managers' index fell to 45.4 in January from 55.4 in December. Analysts had expected the index to increase to 55.9.
That was the lowest level since May 2009.
A reading above 50 indicates a rise in the pace of activity, below 50 indicates a contraction in the pace of activity.
The supplier deliveries index fell to 47.9 from 54.2, while employment index declined to 50.0 from 51.8.
Inventories index dropped to 46.4 from 41.7.