Statistics Canada says wholesale sales decreased 0.4% to $50.5 billion in March after two consecutive monthly gains.
The agency says lower sales were recorded in three of the seven sub-sectors, which together accounted for 51% of wholesale sales.
The motor vehicle and parts sub-sector recorded the largest decline in March, falling 3.0% to $8.1 billion, the lowest level since September 2012.
The nation's number crunchers also say motor vehicle industry, where sales were down 4.4%, accounted for the decrease.
The food, beverage and tobacco sub-sector rose 1.2% to $10.1 billion, the fifth increase in six months.
Lower sales were recorded in five provinces, which together accounted for 60% of wholesale sales.
