The increase from July beat the loss of 0.2 per cent that economists had expected, according to Thomson Reuters.
Excluding the motor vehicle and parts subsector — which had the largest drop — wholesale sales rose 1.0 per cent.
CIBC economist Nick Exarhos noted that the better than expected report followed disappointing manufacturing data for the same month that was released last week.
"Wholesale trade remains on a steep upward trajectory from mid-2013," Exarhos wrote in a note to clients.
Statistics Canada said the machinery, equipment and supplies subsector posted the largest gain for August with a 3.6 per cent increase.
Sales were also up in the miscellaneous subsector, which rose 1.2 per cent while food, beverage and tobacco sales were up 0.3 per cent.
Motor vehicle and parts sales was the leading group on the downside as it fell 3.7 per cent, offsetting most of a 4.5 per cent increase posted in July.
The farm product group was down 1.4 per cent, while personal and household goods fell 0.9 per cent.
Sales of building materials and supplies were unchanged.
In volume terms, wholesale sales edged up 0.1 per cent.
Statistics Canada said sales rose in four provinces in August, which together represented two-thirds of wholesale sales in Canada, with Ontario accounting for much of the gain.