StatsCan said sales fell to the lowest level in six months with sales dropping for the second consecutive month after four months of gains.
Sales fell in five of seven subsectors. The largest decline, minus 3.5 percent, was posted by machinery and equipment wholesale firms, as sales of computer and communication equipment slumped by 13.2 percent, the largest decline within the subsector.
Sales of motor vehicles and parts dropped 4 percent, giving up all of November's gain and then some.
Sales of personal and household goods slipped 1.7 percent. Sales also fell 0.4 percent in building supplies and materials and 0.1 percent in the miscellaneous subsector.
Sales rose for farm products, up 1.4 percent, and for food, beverage and tobacco wholesalers, where sales rose 1.7 percent, StatsCan said.