The computer and equipment subsector's 7.3 percent monthly sales gain was its largest since April 2008, the agency said.
The second-largest gain was in the food, beverage and tobacco subsector, which rose 1.4 percent. Wholesale sales in the motor vehicle and parts subsector grew 1.6 percent on a monthly basis, the report said,
Four of the seven wholesale sectors that account for 70 percent of all sales reported gains in May.
Sales in the miscellaneous sector dipped 0.9 percent in May after a 9.4 percent upward spike in April, StatsCan said.
Regionally, wholesale trade increased in eight of the 10 Canadian provinces, led by Quebec and Alberta, the agency said.