Statistics Canada says wholesale sales, excluding petroleum, petroleum products, and other hydrocarbons and excluding oilseed and grain, fell 0.6% to $82.4 billion in June.
The agency says sales fell in five of the seven subsectors.
Sales in the motor vehicle and motor vehicle parts and accessories subsector fell 2.6% to $14.2 billion as the motor vehicle merchant wholesalers category fell 2.7% to $11.5 billion.
The machinery, equipment and supplies subsector dropped 0.5% to $17.9 billion in June.
In volume terms, wholesale sales fell 0.9% in June.
Statistics Canada started including oilseed and grain as well as the petroleum and petroleum products subsector as part of wholesale trade last year, but is excluding the data from monthly analysis until there is enough historical data.