Portugal, which has traditionally been a country of emigration, has become a receiving country, first from its former colonies, then from the whole world, particularly in recent years from Eastern Europe. Can this new situation be quantified? Has it led to changes in public policy, or to effects on the labour market and on national development? This article addresses the major changes in migration policies and the integration issues they raise. After briefly alluding to the transnational networks of Portuguese migrants, and especially to primarily labour-oriented migration within the European space, the unique position of Portugal with respect to immigration will be considered. An analysis will also be provided of migration policies relating to the legalisation of illegal aliens, as well as of the characteristics and labour-market incorporation of various migrant groups and the prospects for migration flows. Migrants create interdependence between their country of origin and of residence, as shown by the movements of persons and the financial and economic flows that accompany them. Migration issues are thus multiple for Portugal, at the level of policies and of economic and demographic dynamics. A study of the modes of integration of migrant populations thus offers an opportunity to reflect both on the reconciliation of immigration and citizenship and on the challenge that it represents for social Europe.