How do manufacturing plants respond to inter-regional migration in developing countries? To examine this issue, we leverage administrative longitudinal Vietnamese data at manufacturing plant level between 2009 and 2018. We construct an instrument variable for migration flows using exogenous shocks to agricultural incomes at the origin provinces. We find that inter-regional migration increases motivate manufacturing plants to hire more workers in the five-years period. Labour productivity and costs per employee grows; however, firms become more labour intensive.