This article deals with the recruitment and employment of foreign workers in the Italian and Portuguese construction sectors. The two countries show a very similar structure and organisation of the sector. Nevertheless, Italy only "imports" immigrants for the sector whereas Portugal both imports foreign labour and exports construction workers on the European market. On the basis of a comparative analysis of the occupational structure of foreign workers and of interviews with construction employers in the two countries this article examines such differences and discusses how (also with reference to irregular work and the underground economy) and why the construction sector represents a key sector for the economic insertion and adaptation of immigrants in the Mediterranean area. Skills shortages and labour cost issues are highlighted as factors affecting recruitment of foreigners in a sector characterised by a very high level of deregulation and informality, and in which processes of downsizing on the one hand and externalisation on the other have had as an important outcome the nearly exclusive role of subcontracting in the recruitment of semi- and low-skilled workers.