Immigrant and foreign population

As a result of successive waves of migration flows from varying destinations, countries differ in the share and composition of immigrants and foreign population. The definition of these populations is key for international comparisons.


Nationality and place of birth are the two criteria most commonly used to define the “immigrant” population. The foreign-born population covers all persons who have ever migrated from their country of birth to their current country of residence. The foreign population consists of persons who still have the nationality of their home country. It may include persons born in the host country.


The difference across countries between the size of the foreign-born population and that of the foreign population depends on the rules governing the acquisition of citizenship in each country. In some countries, children born in the country automatically acquire the citizenship of their country of birth while in other countries, they retain the nationality of their parents. In some others, they retain the nationality of their parents at birth but receive that of the host country at their majority. Differences in the ease with which immigrants may acquire the citizenship of the host country explain part of the gap between the two. For example, residency requirements vary from as little as four years in Canada to as much as ten years in some other countries.

In general, the foreign-born criterion gives substantially higher percentages for the immigrant population than the definition based on nationality because of naturalisations. The place of birth changes only if country borders change.

Most data are taken from the contributions of national correspondents who are part of the OECD Expert Group on International Migration.

The foreign-born population data shown here include persons born abroad as nationals of their current country of residence. The prevalence of such persons among the foreign-born can be significant in some countries, in particular France and Portugal who received large inflows of repatriates from former colonies.

The EU28 aggregate is a weighted average and does not include Croatia or Malta.


The share of the foreign-born population in the total population is especially high in Luxembourg, Switzerland, New Zealand, Australia, Israel and Canada where it ranges from 20% to 44%. In a number of other countries e.g. Austria, Ireland, Slovenia, Sweden, Belgium, Norway, Spain and the United States the share is above 13%. It has increased in the past decade in all countries for which data are available with the exception of Israel and Estonia.

The proportion of foreign-born in the population as a whole roughly doubled over the past 13 years in Ireland, Norway and Spain. By contrast, the foreign population tends to increase more slowly, because inflows of foreign nationals tend to be counterbalanced by persons acquiring the nationality of the host country.


Further information

Analytical publications

Statistical publications

Methodological publications


Table. Foreign-born and foreign populations

Foreign-born population
As a percentage of total population