October's decline was slightly more than the 0.4 per cent loss that economists had estimated according to Thomson Reuters.
Statistics Canada says the drop was due to lower production of aerospace products and parts.
It adds there was also a decrease in primary metal sales.
Statistics Canada says notwithstanding the lower overall sales, manufacturers in 15 of 21 industries — representing more than 60 per cent of total manufacturing — reported higher sales in October.
It says sales in constant dollars fell 0.5 per cent, indicating that a lower volume of manufactured goods was sold.