One of the most important predictions made in the recent international trade literature based on heterogeneous firms concerns the within-industry job reallocation from firms not involved in international markets to those that are.  This paper quantifies the extent of this reallocation using a data set of Belgian manufacturing firms from 1998 to 2004 having information on their international trading activities.  The results suggest that at three-digit industry levels, the shifts in employment between firms having different trading status account for 6 to 30 percent of total job reallocation.  This effect is stronger for large than for small firms.