In this note, we first depict the structure of the foreign population (When did they come? From where? What about their skills?) and discuss its assimilation on the domestic labor market. Then we evaluate the demand for skilled immigration in the Belgian regions raised by domestic population changes. We demonstrate that replacement immigration is a sustainable policy in Flanders but not in Wallonia and Brussels, where it would jeopardize demographic stability. Using a projection methodology that takes into account the changes in the demand and supply of labor, we then show that an additional flow ranging from 500 to 9,000 skilled immigrants would be necessary to stabilize the Flemish dependency ratio. ; info:eu-repo/semantics/published